Sonic 3 & Knuckles
Sega's 1994 Mega Drive/Genesis platformer, Sonic the Hedgehog 3 and Sonic & Knuckles joined by a lock-on cartridge.
Sonic 3 & Knuckles is Sega’s platformer for the Mega Drive/Genesis, sold as two cartridges that lock together. Sonic the Hedgehog 3 came out first, on 2 February 1994 (North America)1, reaching the UK later that month and Japan in May1. Sega advertised Sonic & Knuckles worldwide for 18 October 19942,2. Fitted into the slot on top of the Sonic & Knuckles cartridge, Sonic 3 makes one 34-megabit game with Knuckles playable3.
Sonic 3 has six zones of two acts each4. One player can be Sonic and Tails together, Sonic alone, or Tails alone, and two players can compete as Sonic, Tails, or Knuckles5. The cartridge keeps six games, each saved when it ends or when the player presses Reset6. Knuckles is Sonic’s rival here, an antagonist who knows the island’s hidden passages and blocks his path7. Sonic & Knuckles also plays on its own, from Mushroom Hill to the Doomsday Zone8, and locked onto Sonic 2 it lets the player go through Sonic 2 as Knuckles9.
Sonic 3 was made at Sega Technical Institute in the United States by an almost wholly Japanese staff10, with Yuji Naka as producer and lead programmer and Hirokazu Yasuhara as director11. Naka said a McDonald’s promotion fixed its release for February 1994, leaving time for only about half the stages planned12. Takashi Iizuka adds that the cartridge couldn’t hold the whole game. Two separate cartridges couldn’t share data, he said, so the Knuckles routes built into Sonic 3’s stages would have been unplayable; the lock-on cartridge solved that13.
Electronic Gaming Monthly made Sonic 3 its Game of the Month14, and in the UK it entered the Mega Drive chart at number 115. Retro Gamer puts the two cartridges’ combined sales at 4 million16 copies16, and its feature on the game says Sonic fans tend to hold Sonic 3 & Knuckles the best of the classic games17.
#How it plays
Sonic builds up speed at the same rate and to the same top speed as in the first two games18, and he falls under the same gravity19. Sonic and Tails take off at one speed and Knuckles slower20. Letting go of the button cuts a fast rise short21. In the air, a Sonic already faster than his top speed keeps that speed, where Sonic 1 and Sonic 2 slowed him to it22. He walks off a ledge with his speed kept, as in Sonic 223, and a jump pressed once he has left it does nothing24.
Crouching and pressing the button charges the spin dash. Each press adds to the charge, and letting go of Down sends him off rolling25 at 8 to 12 px/frame26, as in Sonic 226. Knuckles has the spin dash too27.
Rolling starts and ends differently from Sonic 2. Pressing Down curls a running Sonic into a ball only at twice Sonic 2’s speed; slower than that, unless he stands on an object, he crouches, where Sonic 2 crouched him only from a standstill28. Outside the stretches that force him to roll, a slowing roll stands him up before it stops, and he keeps the speed left, where Sonic 2’s roll runs on to a standstill29. Sonic 3 played alone keeps Sonic 2’s rules for both28,29.
Sonic 3 has three shields, the Flame, Water, and Lightning shields30. Once a jump’s rise has slowed, a second press of the button uses the shield. With no shield, Sonic flashes the insta-shield: for a moment he can’t be hurt, and his box against enemies widens31. With the Flame Shield he dashes forward, with the Lightning Shield he jumps again, and with the Water Shield he drops straight down and bounces on landing32,30. Sonic 3 alone has the same moves33. Each shield also guards him against hazards of its element34, and a hit costs the shield instead of his rings35. Without a shield, a hit scatters his rings, and a hit with none kills him36.
Standing still on flat ground with the floor under his middle far below, Sonic balances on the edge and turns to face the drop. Sonic 2 turned him only when the floor behind him was also that far down37. A steep enough slope pushes even a standing player downhill, which no slope did in Sonic 1 or Sonic 238. A slow climber on a steep slope slips back down it, where those games dropped him off it39.
Tails flies by pressing the button again and again, for 480 frames40 in all40. Knuckles glides, falling slowly while his speed builds41, and he breaks through walls and climbs them27.
#Making it
Sega Technical Institute’s American developers moved to Sonic Spinball while its Japanese staff made Sonic 310. The credits name Hisayoshi Yoshida and Takashi Iizuka as senior game designers and Takashi Thomas Yuda as character designer11. Sonic & Knuckles credits the same leads, with Takahiro Hamano where Sonic 3 names Hiroshi Nikaidoh among the senior programmers42. Naka said Knuckles came out of market research into American children’s tastes, the most popular of eight candidate designs43. Retro Gamer credits his design to Yuda44. Iizuka said the plan from the start was for Knuckles to be an enemy first and playable later7. His punch through rock, Iizuka said, let the team build routes only Knuckles could use, and his climbing and gliding brought vertical play to stages built for Sonic’s running45.
Naka said Sonic 3 was first built for Sega’s SVP chip, and that the team dropped that version in June 1993, when the chip looked unlikely to be ready by the end of the year, and started over with six months left46. Iizuka gives another reason: the SVP work was a research experiment in moving Sonic in 3D, and a chip that handled only about as many polygons as Virtua Racing wasn’t a good fit for a Sonic game47. The developers each explain the split their own way. Naka puts it down to the date: the McDonald’s promotion, on which Sega had spent 2 billion yen, left half the stages unmade, and the idea of joining two cartridges came only at the end of development12. Iizuka says the promotion “wasn’t realistic to change” and names the cartridge’s size13. Roger Hector, head of Sega Technical Institute, said the design was too large to fit in one game48. Mean Machines Sega’s review of Sonic 3 in March 1994 already reported plans for a 24-megabit edition with extra levels, and possibly a plug-through cartridge that would also work with Sonic 1 and Sonic 249.
Retro Gamer reports that the split moved Flying Battery Zone out of Sonic 3 to become Sonic & Knuckles’s second zone50. Iizuka said Launch Base, now Sonic 3’s last zone, got an extra boss, and Mushroom Hill, now Sonic & Knuckles’s first, was made easier than planned51.
The Sonic & Knuckles manual says the cartridge is designed for Sonic 3 or Sonic 2 and won’t work with other cartridges; it doesn’t name Sonic 1. Iizuka said Sonic 1’s stages were built for Sonic and didn’t work with other characters, so the team sent players to the special stages instead9. Game Informer reports that the slot reads the ID of the cartridge on top, and that most other games bring up the blue sphere special stages52.
Sonic 3’s credits name six composers beside Sega’s sound team. Sonic & Knuckles alone credits only Howard Drossin, and the locked-on game credits all seven53. Hector said Michael Jackson was brought in to write the music and dropped at the end of development54. Jackson isn’t credited. VGC reports that Sega has never confirmed his part, and that former Sega executives have said any part he had was without their knowledge55.
#Reception
Electronic Gaming Monthly’s four reviewers all praised Sonic 3. Ed Semrad called it “simply the perfect Sonic game”, though he found its music short of the CD version’s, and Sushi-X said it topped every earlier Sonic14. In April 1995 the magazine ranked it first among the past year’s highest-rated games56. GamePro’s reviewer called it “another spectacular game” but found its acts more linear than the first games’57. Mean Machines Sega gave it 94%58, though its box faulted it for having no difficulty settings58. Sega Power gave it 90%59, finding “no radical changes to the gameplan”59.
Mean Machines Sega scored Sonic & Knuckles lower, at 85%60. Gus found its likeness to Sonic 3 “almost disturbing”, and Steve Merrett called it “more of the same”; the magazine’s box praised the lock-on for putting life into games already bought60. VideoGames gave Sonic & Knuckles an honorable mention among the Genesis games of 1994, behind Earthworm Jim61.
Later reviews single out the saves and Knuckles62. The two games came to the PC and the Saturn in 199763. Sonic Origins brought them back as one game in 2022, without “all the original sounds” of the Genesis game; Sega said Jun Senoue had adapted it64. Iizuka said he had wished to sell the two as one complete game, and was happy that Sonic Origins did65.
Mechanics
| Mechanic | Kind | How |
|---|---|---|
| Jump | One speed | Sonic and Tails take off at one speed, Knuckles slower |
| Gravity | One gravity | the pull of the first two games, the same whether the button is held or not |
| Variable jump height | Release cap | letting go cuts a fast rise short; a second press in the air uses the shield |
| Running | Momentum | the top speed, acceleration, and braking of the first two games |
| Air control | Momentum | the old steering and drag, but a Sonic faster than his top speed keeps that speed in the air |
| Hitbox | Points and a box | ducking no longer shrinks his box, and the insta-shield widens it |
| Invincibility frames | Frame timer | a blinking spell after a hit, counted again from the landing |
| Knockback | Launch | a hit throws him up and back at the speeds of the first two games |
| Rolling | Slopes only | Down curls him only at twice Sonic 2's speed, and a slowing roll stands him up before it stops |
| Spin dash | Charged | Sonic 2's spin dash, which Knuckles has too |
| Slope physics | Even standing | a steep slope pushes even a standing player, and a slow climber slips back down |
| Rings as health | Drop all | a hit scatters his rings, and a hit with none kills |
| Shields | Elemental | the Flame, Lightning, and Water shields guard against their hazards and give Sonic an air move |
| Flight | Flap · Tails | Tails flaps for a few seconds, each press lifting him |
| Flight | Steady glide · Knuckles | Knuckles glides, falling slowly while his speed builds |
| Climbing | Wall · Knuckles | Knuckles climbs walls |
| Password and battery save | six games kept on the Sonic 3 cartridge, each saved when it ends or Reset is pressed | |
| Multiplayer | Versus | two players compete as Sonic, Tails, or Knuckles |
| Coyote time | None | a jump starts only from the ground |
Every claim about this game, by concept (94)
References
- ^ abSonic the Hedgehog 3 came out in North America on 2 February 1994 and in the UK on 24 February; some European countries and Australia followed in March, and Japan on 27 May.InterviewRetro Gamer (GamesRadar), Sonic 3 at 30 · Sega Visions 17 · MMS 17, Mar 1994 · Beep! MD, Jun 1994revised
How we know
Sonic 3 released on 2 February 1994 in North America, and followed to the UK on 24 February, with some European countries and Australia following in March. In Japan, where the Mega Drive was less popular, the game finally released on 27 May.
"Happy blue year" section · archived copy ↗ IN STORE 2/2/94
p. 85, Kay-Bee Toys coupon (archive.org page n88) · archived copy ↗ 24 FEB
p. 13 (archive.org page n12) · archived copy ↗ ソニック3 5/27 4,000円
Santa mail-order advertisement, "MD新作コーナー" (archive.org page n63) · archived copy ↗ Checked against the evidence by its author, an AI model, 2026-10-26.
Revised after a check by a second AI model, 2026-10-26.
- ^ abSega advertised Sonic & Knuckles as "playing worldwide" on the Genesis from 18 October 1994, and a Tokyo shop's advertisement in Beep! MegaDrive lists it in Japan for 18 October.MagazineSega Visions 21 · Beep! MD, Nov 1994 · Retro Gamer (GamesRadar), Sonic 3 at 30revised
How we know
PLAYING WORLDWIDE OCTOBER 18, 1994 ON SEGA GENESIS
p. 43, Sega advertisement "Joining Forces" (archive.org page n44) · archived copy ↗ ソニック&ナックルズ10/18 5,500円
Santa mail-order advertisement, "MD新作コーナー" (archive.org page n51) · archived copy ↗ Released globally in October 1994, Sonic & Knuckles received another strong set of reviews.
"New shoes" section · archived copy ↗ Checked against the evidence by its author, an AI model, 2026-10-26.
Revised after a check by a second AI model, 2026-10-26.
- ^With Sonic 3 fitted into the slot on top of the Sonic & Knuckles cartridge, the two play as one 34-megabit game, Sonic 3 & Knuckles, with 14 Emeralds to collect and Knuckles playable. Its file select offers Sonic, Knuckles, Tails, or Sonic and Tails, and lists the games saved in Sonic 3, which resume from the start of their last zone with the same character.ManualSonic & Knuckles US manual
How we know
Lock-On Sonic 3 with the Sonic & Knuckles cartridge to create a huge, 34 MEG Sonic epic! Sonic 3 & Knuckles has more gameplay options in 1 Player mode. New secrets wait to be found, and now you've got 14 Emeralds to rescue! Play as Knuckles and discover new routes!
p. 2 · archived copy ↗ Lift up the flap on the top of the Sonic & Knuckles cartridge, and fit the Sonic 3 cartridge into it
p. 21 · archived copy ↗ now you can play Sonic 3 & Knuckles as Sonic, Knuckles, Tails, or Sonic and Tails!
p. 23 · archived copy ↗ You must play as the character who played the original game. … You will resume the game from the beginning of the last Zone that was played.
p. 24 · archived copy ↗ The quote matches our archived copy.
Checked by a second AI model, 2026-10-26.
- ^The Sonic 3 manual describes six zones of two acts each, which it calls three times larger than Sonic 2's.ManualSonic 3 US manual
How we know
You'll soon discover that Sonic The Hedgehog 3 is packed with Zones which are three times larger than those found in Sonic The Hedgehog 2. Each Zone is made up of two Acts … As Sonic and Tails explore the six exciting Zones
p. 5 · archived copy ↗ The quote matches our archived copy.
Checked by a second AI model, 2026-10-26.
- ^Sega Visions' preview of Sonic 3 lists a one-player game as Sonic and Tails, Sonic alone, or Tails alone, a two-player competition with Sonic, Tails, or Knuckles over three modes and five zones, and six spaces for saved games.MagazineSega Visions 17
How we know
Now you can save your games in one of six save spaces. In the one- player mode you have the choice of playing as Sonic and Tails, Sonic-alone or Tails alone. … The two-player, head-to-head competition mode offers players the choice of playing as Sonic, Tails or Knuck- les. There are three different Competitive modes and five Competitive zones.
Sonic 3 preview (archive.org page n21) · archived copy ↗ The quote matches our archived copy.
Checked by a second AI model, 2026-10-26.
- ^Sonic 3 keeps up to six games in the cartridge, and a game is saved to its slot when it ends or when the player presses Reset.ManualSonic 3 US manual
How we know
allows you to store game data for up to … will be stored in one of the six Game Save Windows. … After your game is over, or if you press RESET, your game will automatically be saved in the slot you selected.
p. 10, Game Save Feature · archived copy ↗ The quote matches our archived copy.
Checked by a second AI model, 2026-10-26.
- ^ abIn Sonic 3, Knuckles is an antagonist who knows the island's hidden passages and blocks Sonic's path. Takashi Iizuka said the plan from the start was that Knuckles would first be an enemy and later become playable.ManualSonic 3 US manual · Retro Gamer (GamesRadar), Sonic 3 at 30
How we know
Because Knuckles knows every hidden passage- way on the island, it's easy for him to block Sonic's path, create extra obstacles, set traps and steal Sonic's Gold Rings.
p. 6 · archived copy ↗ We had the idea from the beginning that Knuckles would first be an enemy but later become playable. So we worked Knuckles into the story and had him appear as an enemy from the outset,
Iizuka on Knuckles in the story · archived copy ↗ The quote matches our archived copy.
Checked by a second AI model, 2026-10-26.
- ^Sonic & Knuckles plays on its own, and its manual's zones are Mushroom Hill, Flying Battery, Sandopolis, Lava Reef, Hidden Palace, Sky Sanctuary, Death Egg, and the Doomsday Zone.ManualSonic & Knuckles US manual
How we know
It's the first game cartridge ever that you can play by itself, or Lock-On with other Sonic game cartridges!
p. 2 · archived copy ↗ Mushroom Hill Zone ~~~~~~~~~~~~~~~~~~ 12 Flying Battery Zone ~~~~~~~~~~~~~~~~~~~ 12 Sandopolis Zone ~~~~~~~~~~~~~~~~~~~~~~ 13 Lava Reef Zone ~~~~~~~~~~~~~~~~~~~~~~~ 13 Hidden Palace Zone ~~~~~~~~~~~~~~~~~~~ 14 Sky Sanctuary Zone ~~~~~~~~~~~~~~~~~~~ 14 Death Egg Zone ~ Doomsday Zone
contents page · archived copy ↗ The quote matches our archived copy.
Checked by a second AI model, 2026-10-26.
- ^ abLocked onto Sonic 2, the cartridge lets the player go through Sonic 2 as Knuckles. The manual says it is designed for Sonic 3 or Sonic 2 and "will not work with non-Sonic cartridges"; it names no other cartridge, Sonic 1 included. Takashi Iizuka said Sonic 1's world was built for Sonic and didn't work right with other characters, so the team sent players to the special stages instead.ManualSonic & Knuckles US manual · Game Informer, Sonic 3 splitrevised
How we know
Lock-On Sonic 2 to the Sonic & Knuckles cartridge to experience a totally new Sonic 2 adventure as Knuckles with all his signature moves! … The Sonic & Knuckles cartridge is designed to Lock-On with a Sonic3 ora Sonic 2 cartridge. It will not work with non-Sonic cartridges.
p. 2 · archived copy ↗ We realized that the construction of the world was really made for Sonic the Hedgehog 1 and when you started putting other characters into that world, it didn't really work right, … So our solution to that was instead of getting you into Sonic the Hedgehog 1 and trying to play with Knuckles or someone else, we didn't want people to have a bad experience, so we put them into the special stages.
"Stacking Other Games on Sonic & Knuckles" · archived copy ↗ The quote matches our archived copy.
Revised after a check by a second AI model, 2026-10-26.
- ^ abSonic 3 was made at Sega Technical Institute in the United States by an almost wholly Japanese staff, while the institute's American developers moved to Sonic Spinball; Sega-16's history of the institute says the Japanese unit made both Sonic 3 and Sonic & Knuckles.InterviewRetro Gamer (GamesRadar), Sonic 3 at 30 · Sega-16, STI history · Sega Magazine JP 1997, via Shmuplations
How we know
while Sonic development continued at STI, the American developers would split off to work on Sonic Spinball, while Sonic The Hedgehog 3 was developed at Sega Technical Institute in the USA with almost exclusively Japanese staff.
on the team · archived copy ↗ The group was broken up into smaller units, with the Americans dedicating themselves to mostly original titles, and the Japanese concentrating on Sonic sequels, like Sonic 3 and Sonic & Knuckles.
after Sonic 2 · archived copy ↗ At the end of the Sonic 2 development, we had a hell of a time coordinating with the American staff, and for that reason, for Sonic 3 we decided to make Sonic 3 with an all-japanese team.
Naka, on Sonic 3 · archived copy ↗ The quote matches our archived copy.
Checked by a second AI model, 2026-10-26.
- ^ abSonic 3's credits name Yuji Naka as producer and lead programmer, Hirokazu Yasuhara as director and lead game designer, Hisayoshi Yoshida and Takashi Iizuka as senior game designers, Hiroshi Nikaidoh and Masanobu Yamamoto as senior programmers, and Takashi Thomas Yuda as character designer.Codesonicretro/skdisasm
How we know
77532 dc.b "producer",0 77533 even 77534 dc.w $798 77535 dc.b "YUJ I NAKA",0 77536 even 77537word_40C5E: dc.w 2-1 77538 dc.w $498 77539 dc.b " director",0 77540 even 77541 dc.w $786 77542 dc.b "HIROKAZU YASUHARA",0 77543 even ⋮
s3.asm lines 77532–77583 at 73de97c · upstream ↗ Checked against the evidence by its author, an AI model, 2026-10-26.
Checked by a second AI model, 2026-10-26.
- ^ abYuji Naka said a McDonald's promotion planned for February 1994, on which Sega had spent 2 billion yen, fixed Sonic 3's release date, so after the restart the team had time for only about half the stages it had planned; the idea of joining two cartridges came only at the end of development. He later told GameSpy that Sonic 3 was "literally half a game", the rest going into Sonic & Knuckles.InterviewSega Magazine JP 1997, via Shmuplations · GameSpy, Naka interview
How we know
we had planned a big promotional tie-in campaign with McDonald’s the following year in February—and we had spent 2 billion yen (approx 20 million USD) on it!—so we absolutely had to meet that release deadline for Sonic 3 in February. Unfortunately, having to restart everything in June, we only had time to create about half the stages we’d envisioned. … Then, at the very end of the Sonic 3 development, we were talking about needing to do something, and someone asked if it would be technically possible to combine two cartridges. We figured out the way to do that at the very, very last minute before the deadline, and then we revised all the programming in Sonic 3 to account for a future Lock-On cart.
Naka, on Sonic 3 · archived copy ↗ Sonic 3 is literally half a game. Sega management back then wanted the game out at a certain time and we only had half the stages done, so we had to put the leftovers into Sonic and Knuckles.
p. 4 · archived copy ↗ The quote matches our archived copy.
Checked by a second AI model, 2026-10-26.
- ^ abTakashi Iizuka said the team wanted more stages, each several times larger than Sonic 2's, but it had a date to meet and the cartridge couldn't hold the whole game; of the promotion that set the date, he told Retro Gamer "it wasn't realistic to change that". He said splitting it would have left the Knuckles routes built into Sonic 3's stages unplayable, since two cartridges couldn't share data, and that this led to the lock-on cartridge.WebGame Informer, Sonic 3 split · Retro Gamer (GamesRadar), Sonic 3 at 30revised
How we know
We wanted bigger maps multiple times larger than Sonic 2, but we also wanted to have more maps … The cartridge sizes were limited in space, so we were finding out that not only did we have these obligations to get the content out at a certain time, but we also couldn't get this massive game that we wanted to make onto the space that the cart would allow,
Iizuka on Sonic 3 · archived copy ↗ Takashi Iizuka confirms that "it wasn't realistic to change that" promotion
on the SVP chip and the deadline · archived copy ↗ Data couldn't be carried over if we used two separate cartridges, making the Knuckles routes we had built into the Sonic 3 stages unplayable. That's where the idea came for the Lock-On cartridge, allowing the two cartridges to work together.
Iizuka on the split · archived copy ↗ The quote matches our archived copy.
Revised after a check by a second AI model, 2026-10-26.
- ^ abElectronic Gaming Monthly made Sonic 3 its Game of the Month with an Editors' Choice Platinum award. Ed Semrad called it "simply the perfect Sonic game", though its music was not as good as the CD version's; Danyon Carpenter said it improved on the original "tenfold"; Al Manuel liked it better than the CD version; and Sushi-X said it topped every earlier Sonic.MagazineEGM 56, Mar 1994revised
How we know
GAME OF THE MONTH
p. 30, Review Crew (archive.org page n29) · archived copy ↗ EDITORS' CHOICE PLATINUM
p. 30, Review Crew · archived copy ↗ Sonic 3 is simply the perfect Sonic game. It beats out all the previous Sonics with outstanding graphics, more hidden items and new items like the many types of shields. While the music is not as good as the CD version (I'm not expecting it to be...) it's still really well done.
p. 30, Ed Semrad · archived copy ↗ Sonic 3 completely blows away everything you've ever seen in an action game. This game improves upon the original tenfold!
p. 30, Danyon Carpenter · archived copy ↗ I actually like this game better than the CD version.
p. 30, Al Manuel · archived copy ↗ This one definitely tops any of the previous Sonic versions.
p. 30, Sushi-X · archived copy ↗ Checked against the evidence by its author, an AI model, 2026-10-26.
Revised after a check by a second AI model, 2026-10-26.
- ^Sonic 3 entered the ELSPA Mega Drive chart printed in Sega Power's May 1994 issue at number 1.MagazineSega Power 54, May 1994
How we know
It's good to see a new entry smashing to the top - and not just any new entry. Welcome to Sonic 3.
p. 12, The Charts (file 0006.webp) · archived copy ↗ Checked against the evidence by its author, an AI model, 2026-10-26.
Checked by a second AI model, 2026-10-26.
- ^ abcRetro Gamer reports that Sonic 3 and Sonic & Knuckles together sold four million copies.InterviewRetro Gamer (GamesRadar), Sonic 3 at 30
How we know
Overall, Sonic 3 and Sonic & Knuckles combined sold four million copies.
"New shoes" section · archived copy ↗ The quote matches our archived copy.
Checked by a second AI model, 2026-10-26.
- ^Retro Gamer's feature on Sonic 3, republished online in 2024, says Sonic fans tend to hold Sonic 3 & Knuckles the best of the classic games. Jeremy Parish's 2013 USgamer list of the best Genesis games put Sonic & Knuckles eighth, counting votes for Sonic 3 & Knuckles with it, and Eurogamer's Dan Whitehead wrote in 2009 that Sonic 3's stages "now sprawl in many directions".InterviewRetro Gamer (GamesRadar), Sonic 3 at 30 · USgamer, best Genesis games · Eurogamer, Sega Vintage Collectionrevised
How we know
Sonic fans tend to hold Sonic 3 & Knuckles as the best of the classics.
closing section · archived copy ↗ 8. Sonic & Knuckles I fudged a little bit on tallying this one, because votes were split between Sonic & Knuckles and Sonic 3 & Knuckles.
8. Sonic & Knuckles · archived copy ↗ Size is one of the major changes, with stages that now sprawl in many directions.
Sonic the Hedgehog 3 · archived copy ↗ The quote matches our archived copy.
Revised after a check by a second AI model, 2026-10-26.
- ^
Sonic_Initsets the top speed to$600, the acceleration to$C, and the deceleration to$80subpixels, the values of Sonic 1 and Sonic 2.Codesonicretro/skdisasm · sonicretro/s1disasm · sonicretro/s2disasmrevisedHow we know
21950 move.w #$600,Max_speed-Max_speed(a4) 21951 move.w #$C,Acceleration-Max_speed(a4) 21952 move.w #$80,Deceleration-Max_speed(a4)
sonic3k.asm lines 21950–21952 at 73de97c · upstream ↗ 22902 add.w d5,d0 22903 cmp.w d6,d0 22904 blt.s loc_114AA 22905 sub.w d5,d0 22906 cmp.w d6,d0 22907 bge.s loc_114AA 22908 move.w d6,d0
sonic3k.asm lines 22902–22908 at 73de97c · upstream ↗ 5son_maxspeed: equ $600 ; Sonic's max speed 6son_acceleration: equ $C ; Sonic's acceleration 7son_deceleration: equ $80 ; Sonic's deceleration
_incObj/01 Sonic.asm lines 5–7 at 15dfa3a · upstream ↗ 36232 move.w #$600,(Sonic_top_speed).w ; set Sonic's top speed 36233 move.w #$C,(Sonic_acceleration).w ; set Sonic's acceleration 36234 move.w #$80,(Sonic_deceleration).w ; set Sonic's deceleration
s2.asm lines 36232–36234 at 4ef457c · upstream ↗ 37001 sub.w d5,d0 ; remove this frame's acceleration changes2.asm lines 36998–37004 at 4ef457c · upstream ↗ Checked against the evidence by its author, an AI model, 2026-10-21.
Revised after a check by a second AI model, 2026-10-21.
- ^
MoveSpriteadds$38subpixels/frame to a falling player's speed, Sonic 1's and Sonic 2's gravity, and underwater the air modes take$28back.Codesonicretro/skdisasm · sonicretro/s1disasm · sonicretro/s2disasmrevisedHow we know
36077 move.w y_vel(a0),d0 ; load y speed 36078 addi.w #$38,y_vel(a0) ; increase vertical speed (apply gravity)
sonic3k.asm lines 36077–36078 at 73de97c · upstream ↗ 22446 jsr (MoveSprite_TestGravity).l ⋮ 22449 subi.w #$28,y_vel(a0) ; reduce gravity by $28 ($38-$28=$10)
sonic3k.asm lines 22442–22449 at 73de97c · upstream ↗ gravity: equ $38
_incObj/sub ObjectFall & SpeedToPos.asm#L5 · upstream ↗ 30217 addi.w #$38,y_vel(a0) ; increase vertical speed (apply gravity)s2.asm line 30217 at 4ef457c · upstream ↗ Checked against the evidence by its author, an AI model, 2026-10-21.
Revised after a check by a second AI model, 2026-10-21.
- ^Sonic and Tails take off at
$680subpixels per frame (6.5 px/frame) and Knuckles at$600(6 px/frame); underwater the speeds are$380and$300.Codesonicretro/skdisasmHow we know
23342 move.w #$680,d2 ⋮ 23345 move.w #$800,d2 ; set higher jump speed if super ⋮ 23350 move.w #$380,d2 ; set lower jump speed if under
sonic3k.asm lines 23342–23350 at 73de97c · upstream ↗ 28578 move.w #$680,d2 28579 btst #Status_Underwater,status(a0) ⋮ 28581 move.w #$380,d2
sonic3k.asm lines 28578–28581 at 73de97c · upstream ↗ 32494 move.w #$600,d2 32495 btst #Status_Underwater,status(a0) 32496 beq.s loc_1775C 32497 move.w #$300,d2
sonic3k.asm lines 32494–32497 at 73de97c · upstream ↗ Checked against the evidence by its author, an AI model, 2026-10-21.
Checked by a second AI model, 2026-10-21.
- ^With no jump button held,
Sonic_JumpHeightcuts a rise faster than 4 px/frame to exactly-$400(-$200underwater); a press once the rise is no faster than that starts a shield move instead.Codesonicretro/skdisasmrevisedHow we know
23404 move.w #-$400,d1 ⋮ 23407 move.w #-$200,d1 ; Underwater-specific ⋮ 23410 cmp.w y_vel(a0),d1 ; is y speed greater than 4? (2 if underwater) 23411 ble.w Sonic_ShieldMoves ; if not, branch ⋮ 23415 move.w d1,y_vel(a0) ; cap jump height
sonic3k.asm lines 23404–23415 at 73de97c · upstream ↗ Checked against the evidence by its author, an AI model, 2026-10-21.
Checked by a second AI model, 2026-10-21.
Revised after a check by a second AI model, 2026-10-26.
- ^In the air
Sonic_ChgJumpDirstill adds$18a frame, but a Sonic already faster than the top speed keeps his speed; Sonic 1 and Sonic 2 pulled him down to it.Codesonicretro/skdisasm · sonicretro/s2disasm · sonicretro/s1disasmrevisedHow we know
23134 sub.w d5,d0 ; add acceleration to the left ⋮ 23139 add.w d5,d0 ; remove this frame's acceleration change 23140 cmp.w d1,d0 ; compare speed with top speed 23141 ble.s loc_11682 ; if speed was already greater than the maximum, branch 23142 move.w d1,d0
sonic3k.asm lines 23129–23155 at 73de97c · upstream ↗ 20850 add.w d5,d0 ; remove this frame's acceleration change 20851 cmp.w d1,d0 ; compare speed with top speed 20852 ble.s loc_126F2 ; if speed was already greater than the maximum, branch
s3.asm lines 20845–20866 at 73de97c · upstream ↗ 37219 move.w d1,d0 ; limit speed in air going left, even if Sonic was already going faster (speed limit/cap)s2.asm lines 37214–37219 at 4ef457c · upstream ↗ 951 sub.w d5,d0 ; increase leftward movement speed ⋮ 954 cmp.w d1,d0 ; is new speed exceeding maximum? 955 bgt.s .notleft ; if not, branch 956 move.w d1,d0 ; cap leftward X-speed to maximum
_incObj/01 Sonic.asm lines 951–956 at 15dfa3a · upstream ↗ Checked against the evidence by its author, an AI model, 2026-10-21.
Revised after a check by a second AI model, 2026-10-21.
- ^On flat ground, not on an object, when both floor sensors find the floor more than |X speed's high byte| + 4 px below, at most 14, Sonic leaves the ground with his speeds as they are, unless stick_to_convex is set; closer than that, he moves down to it. Sonic 2 has the same rule; Sonic 1 used a flat 14 px.Codesonicretro/skdisasm · sonicretro/s2disasm · sonicretro/s1disasmrevised
How we know
18853loc_ED14: ⋮ 18856 move.b x_vel(a0),d0 ⋮ 18858 neg.b d0 ⋮ 18861 addq.b #4,d0 18862 cmpi.b #$E,d0 ⋮ 18864 move.b #$E,d0 ⋮ 18867 cmp.b d0,d1 18868 bgt.s loc_ED38 ⋮ 18871 add.w d1,y_pos(a0) ⋮ 18875loc_ED38: 18876 bset #Status_InAir,status(a0)
sonic3k.asm lines 18853–18879 at 73de97c · upstream ↗ 43135loc_1E31E: 43136 mvabs.b x_vel(a0),d0 43137 addq.b #4,d0 43138 cmpi.b #$E,d0 43139 blo.s + 43140 move.b #$E,d0 ⋮ 43142 cmp.b d0,d1 43143 bgt.s loc_1E33C
s2.asm lines 43135–43143 at 4ef457c · upstream ↗ 100 cmpi.w #$E,d1 101 bgt.s .in_air ; branch if Sonic is > 14px above floor
_incObj/Sonic AnglePos.asm lines 100–101 at 15dfa3a · upstream ↗ 18854 tst.b stick_to_convex(a0)sonic3k.asm line 18854 at 73de97c · upstream ↗ Checked against the evidence by its author, an AI model, 2026-10-26.
Revised after a check by a second AI model, 2026-10-26.
- ^Sonic 3 & Knuckles has no grace window after a ledge:
Sonic_Jumpis called only from the grounded modes.Codesonicretro/skdisasmHow we know
22328Sonic_MdNormal: 22329 bsr.w SonicKnux_Spindash 22330 bsr.w Sonic_Jump
sonic3k.asm lines 22328–22330 at 73de97c · upstream ↗ 22402Sonic_MdRoll: 22403 tst.b spin_dash_flag(a0) 22404 bne.s loc_10FEA 22405 bsr.w Sonic_Jump
sonic3k.asm lines 22402–22405 at 73de97c · upstream ↗ sonic3k.asm#L22385-L22389 · upstream ↗ Checked against the evidence by its author, an AI model, 2026-10-21.
Checked by a second AI model, 2026-10-21.
- ^Crouching (animation 8), a press of A, B, or C starts the spin dash's charge at 0; while Down stays held, each frame first takes 1/32 of the counter (rounded down) and a press adds
$200, to$800; letting go of Down releases it, curling him (5 px down) and setting the ground speed from the counter's high byte (spindash; Super Sonic's table is faster), negated facing left. On the start, charge, and release frames he doesn't move, and the floor sensors still run. The charge's decay, step, and cap are Sonic 2's.Codesonicretro/skdisasm · sonicretro/s2disasmrevisedHow we know
23681SonicKnux_Spindash: 23682 tst.b spin_dash_flag(a0) 23683 bne.s loc_11C5E 23684 cmpi.b #8,anim(a0) ⋮ 23686 move.b (Ctrl_1_pressed_logical).w,d0 23687 andi.b #button_A_mask|button_B_mask|button_C_mask,d0 ⋮ 23692 addq.l #4,sp 23693 move.b #1,spin_dash_flag(a0) 23694 move.w #0,spin_dash_counter(a0)
sonic3k.asm lines 23679–23696 at 73de97c · upstream ↗ 23739 move.b #0,spin_dash_flag(a0) ⋮ 23741 move.b spin_dash_counter(a0),d0 ⋮ 23743 move.w word_11CF2(pc,d0.w),ground_vel(a0)
sonic3k.asm lines 23737–23746 at 73de97c · upstream ↗ 23770 jsr (Play_SFX).l 23771 bra.s loc_11D5E
sonic3k.asm lines 23770–23771 at 73de97c · upstream ↗ 23798 move.w spin_dash_counter(a0),d0 23799 lsr.w #5,d0 23800 sub.w d0,spin_dash_counter(a0) ⋮ 23811 addi.w #$200,spin_dash_counter(a0) 23812 cmpi.w #$800,spin_dash_counter(a0) ⋮ 23816loc_11D5E: 23817 addq.l #4,sp
sonic3k.asm lines 23796–23822 at 73de97c · upstream ↗ 37715 lsr.w #5,d0 37716 sub.w d0,spindash_counter(a0) ⋮ 37726 addi.w #$200,spindash_counter(a0) 37727 cmpi.w #$800,spindash_counter(a0)
s2.asm lines 37714–37729 at 4ef457c · upstream ↗ Checked against the evidence by its author, an AI model, 2026-10-26.
Revised after a check by a second AI model, 2026-10-26.
- ^ abThe spin dash is Sonic 2's, with the same
$200a press to$800, the same 1/32 decay, and the same release speeds from$800to$C00.Codesonicretro/skdisasm · sonicretro/s2disasmrevisedHow we know
23741 move.b spin_dash_counter(a0),d0 23742 add.w d0,d0 23743 move.w word_11CF2(pc,d0.w),ground_vel(a0)
sonic3k.asm lines 23740–23743 at 73de97c · upstream ↗ 23773word_11CF2: 23774 dc.w $800 23775 dc.w $880
sonic3k.asm lines 23773–23782 at 73de97c · upstream ↗ 23799 lsr.w #5,d0 23800 sub.w d0,spin_dash_counter(a0) ⋮ 23811 addi.w #$200,spin_dash_counter(a0) 23812 cmpi.w #$800,spin_dash_counter(a0)
sonic3k.asm lines 23798–23814 at 73de97c · upstream ↗ 37688SpindashSpeeds: 37689 dc.w $800 ; 0 ⋮ 37697 dc.w $C00 ; 8
s2.asm lines 37688–37697 at 4ef457c · upstream ↗ 37715 lsr.w #5,d0 37716 sub.w d0,spindash_counter(a0) ⋮ 37726 addi.w #$200,spindash_counter(a0) 37727 cmpi.w #$800,spindash_counter(a0)
s2.asm lines 37714–37729 at 4ef457c · upstream ↗ Checked against the evidence by its author, an AI model, 2026-10-21.
Revised after a check by a second AI model, 2026-10-21.
- ^ abThe Sonic & Knuckles manual gives Knuckles the spin dash and moves of his own: he breaks through walls, glides on a second press of the button in the air, and climbs walls.ManualSonic & Knuckles US manual
How we know
Knuckles uses a Spin Dash just like Sonic, but he also. has unique moves of his own. For one thing, he bashes through walls like nobody else! … Glide + Press Button A, Bor C twice quickly — once to get some air and again to start gliding. … Wall Climb ® Get close to a wall.
Knuckles' moves · archived copy ↗ The quote matches our archived copy.
Checked by a second AI model, 2026-10-26.
- ^ abWith Down held, neither Left nor Right, and no infinite-inertia flag (bit 7 of status_secondary), Sonic curls into a roll at a ground speed of
$100or more either way, twice Sonic 2's$80; slower than that, unless he stands on an object, he crouches, where Sonic 2 and Sonic 3 alone crouch only fromSonic_Move's standstill branch.Codesonicretro/skdisasm · sonicretro/s2disasmrevisedHow we know
23258SonicKnux_Roll: ⋮ 23262 andi.b #button_left_mask|button_right_mask,d0 ; is left/right being pressed? 23263 bne.s locret_1177E ; if yes, branch 23264 btst #button_down,(Ctrl_1_logical).w ; is down being pressed? ⋮ 23271 cmpi.w #$100,d0 ; is Sonic moving at $100 speed or faster? 23272 bhs.s Player_ChkRoll ; if so, branch 23273 btst #Status_OnObj,status(a0) 23274 bne.s locret_1177E 23275 move.b #8,anim(a0) ; enter ducking animation
sonic3k.asm lines 23258–23278 at 73de97c · upstream ↗ 37345 mvabs.w inertia(a0),d0 37346 cmpi.w #$80,d0 ; is Sonic moving at $80 speed or faster? 37347 blo.s Obj01_NoRoll ; if not, branch
s2.asm lines 37345–37352 at 4ef457c · upstream ↗ 20970 cmpi.w #$80,d0 ; is Sonic moving at $80 speed or faster? 20971 blo.s locret_127D0 ; if so, branch
s3.asm lines 20970–20976 at 73de97c · upstream ↗ 36788Sonic_Duck: 36789 btst #button_down,(Ctrl_1_Held_Logical).w ; is down being pressed? 36790 beq.s Obj01_ResetScr ; if not, branch 36791 move.b #AniIDSonAni_Duck,anim(a0) ; use "ducking" animation
s2.asm lines 36788–36791 at 4ef457c · upstream ↗ 20420loc_12362: 20421 btst #button_down,(Ctrl_1_held_logical).w 20422 beq.s loc_1238C 20423 move.b #8,anim(a0)
s3.asm lines 20420–20423 at 73de97c · upstream ↗ Checked against the evidence by its author, an AI model, 2026-10-26.
Revised after a check by a second AI model, 2026-10-26.
- ^ abOutside pinball mode (spin_dash_flag set on a roll) and without the infinite-inertia flag, a roll ends once friction and the d-pad leave the ground speed under
$80either way, and the speed left is kept; Sonic 2 and Sonic 3 alone unroll only at 0. Standing up moves his center 5 px up with normal gravity. In pinball mode a positive flag sets the speed to$400in his facing direction instead, and a negative one skips the d-pad, friction, and this check.Codesonicretro/skdisasm · sonicretro/s2disasmrevisedHow we know
23007 move.w ground_vel(a0),d0 ⋮ 23012 cmpi.w #$80,d0 23013 bhs.s loc_115C6 ⋮ 23016 bclr #Status_Roll,status(a0) 23017 move.b y_radius(a0),d0 23018 move.b default_y_radius(a0),y_radius(a0) ⋮ 23021 sub.b default_y_radius(a0),d0 ⋮ 23028 add.w d0,y_pos(a0)
sonic3k.asm lines 23007–23028 at 73de97c · upstream ↗ 37097Sonic_CheckRollStop: 37098 tst.w inertia(a0) 37099 bne.s Obj01_Roll_ResetScr ⋮ 37102 bclr #status.player.rolling,status(a0) ⋮ 37106 subq.w #5,y_pos(a0)
s2.asm lines 37097–37106 at 4ef457c · upstream ↗ 20728 tst.w ground_vel(a0) 20729 bne.s loc_12636 ⋮ 20732 bclr #Status_Roll,status(a0)
s3.asm lines 20728–20739 at 73de97c · upstream ↗ 22970 tst.b spin_dash_flag(a0) 22971 bmi.w loc_115C6 22972 tst.b status_secondary(a0) 22973 bmi.w loc_115C6
sonic3k.asm lines 22970–22973 at 73de97c · upstream ↗ 23032loc_115B4: 23033 move.w #$400,ground_vel(a0) 23034 btst #Status_Facing,status(a0) 23035 beq.s loc_115C6 23036 neg.w ground_vel(a0)
sonic3k.asm lines 23032–23036 at 73de97c · upstream ↗ Checked against the evidence by its author, an AI model, 2026-10-26.
Revised after a check by a second AI model, 2026-10-26.
- ^ abThe Sonic 3 manual introduces three shields: the Flame Shield guards against fire and gives Sonic a mid-air dash, the Water Shield lets him breathe underwater and bounce, and the Lightning Shield draws rings to him, guards against electric attacks, and gives him a double jump.ManualSonic 3 US manual
How we know
Flame Shield - Protects Sonic and Tails from a fire attack. When this shield is activated, Sonic can perform a mid-air "Fireball Spin Dash" … Water Shield - Sonic and Tails can breathe underwater and bounce like a
p. 12, Sonic Power-Ups · archived copy ↗ Lightning Shield - When activated, Gold Rings will gravitate towards Sonic or Tails. This shield will also protect Sonic and Tails from electric attacks and energy ball attacks from Badniks. While this shield is active, Sonic can double jump in mid-air
p. 13, Sonic Power-Ups (Continued) · archived copy ↗ The quote matches our archived copy.
Checked by a second AI model, 2026-10-26.
- ^With no shield, the press gives Sonic the insta-shield, which while active makes him invincible and widens his hit box to 48 × 48 px.Codesonicretro/skdisasm
How we know
23509 btst #Status_Shield,status_secondary(a0) ; does Sonic have an S2 shield? (the elementals were already filtered out at this point) 23510 bne.s locret_11A14 ; if yes, branch 23511 move.b #1,(Shield+anim).w 23512 move.b #1,double_jump_flag(a0)
sonic3k.asm lines 23508–23514 at 73de97c · upstream ↗ 20656 cmpi.b #1,double_jump_flag(a0) ; Is the Insta-Shield currently in its 'attacking' mode? ⋮ 20660 bset #Status_Invincible,status_secondary(a0) ; Make the player invincible ⋮ 20665 move.w #$30,d4 ; Player's width 20666 move.w #$30,d5 ; Player's height
sonic3k.asm lines 20656–20666 at 73de97c · upstream ↗ Checked against the evidence by its author, an AI model, 2026-10-21.
Checked by a second AI model, 2026-10-21.
- ^A second press during a jump, once the rise is no faster than 4 px/frame (2 underwater), uses the shield: fire dashes at 8 px/frame and stops the fall, lightning jumps again at
-$580, and bubble stops dead and drops at 8 px/frame, then bounces at 7.5 px/frame on landing.Codesonicretro/skdisasmrevisedHow we know
23400Sonic_JumpHeight: 23401 tst.b jumping(a0) ; is Sonic jumping? 23402 beq.s Sonic_UpVelCap ; if not, branch ⋮ 23411 ble.w Sonic_ShieldMoves ; if not, branch
sonic3k.asm lines 23400–23411 at 73de97c · upstream ↗ 23453 move.w #$800,d0 ⋮ 23461 move.w #0,y_vel(a0) ; kill y-velocity ⋮ 23473 move.w #-$580,y_vel(a0) ; bounce Sonic up, creating the double jump effect ⋮ 23486 move.w #$800,y_vel(a0) ; force Sonic down
sonic3k.asm lines 23446–23488 at 73de97c · upstream ↗ 24436BubbleShield_Bounce: 24437 movem.l d1-d2,-(sp) 24438 move.w #$780,d2 24439 btst #Status_Underwater,status(a0) 24440 beq.s loc_12246 24441 move.w #$400,d2
sonic3k.asm lines 24436–24441 at 73de97c · upstream ↗ Checked against the evidence by its author, an AI model, 2026-10-21.
Revised after a check by a second AI model, 2026-10-21.
Revised after a check by a second AI model, 2026-10-26.
- ^Sonic 3 alone (
s3.asm) has the same shield moves and insta-shield; its transformation check asks only for the seven Chaos Emeralds and 50 rings.Codesonicretro/skdisasmHow we know
21129 move.w #$800,d0 ⋮ 21170Sonic_CheckTransform:
s3.asm lines 21122–21184 at 73de97c · upstream ↗ Checked against the evidence by its author, an AI model, 2026-10-21.
Checked by a second AI model, 2026-10-21.
- ^An elemental shield makes the player immune to each object whose
shield_reactionbyte names that element, and any shield deflects objects flagged for it at 8 px/frame.Codesonicretro/skdisasmHow we know
21043 and.b shield_reaction(a1),d0 ; Does one of the player's shields grant immunity to this object?? ⋮ 21066 andi.b #1<<3,d0 ; Should the object be bounced away by a shield? ⋮ 21076 muls.w #-$800,d1
sonic3k.asm lines 21039–21083 at 73de97c · upstream ↗ Checked against the evidence by its author, an AI model, 2026-10-21.
Checked by a second AI model, 2026-10-21.
- ^A hit with any shield costs the shield, not the rings;
HurtCharacterclears the shield bit and all three element bits together (`andi.bCodesonicretro/skdisasmHow we know
21110 btst #0,status_secondary(a0) 21111 bne.s loc_102DA ⋮ 21117 bne.s loc_102DA ⋮ 21123loc_102DA: 21124 andi.b #$8E,status_secondary(a0)
sonic3k.asm lines 21110–21124 at 73de97c · upstream ↗ 184Status_Shield = 0 185Status_Invincible = 1 186Status_SpeedShoes = 2
sonic3k.constants.asm lines 184–190 at 73de97c · upstream ↗ Checked against the evidence by its author, an AI model, 2026-10-21.
Checked by a second AI model, 2026-10-21.
- ^Hit without a shield, the player drops his rings, at most 32 as bouncing rings, and the count goes to 0; with no rings he dies.Codesonicretro/skdisasm
How we know
21102 move.w (Ring_count).w,d0 ⋮ 21110 btst #0,status_secondary(a0) 21111 bne.s loc_102DA ⋮ 21114 tst.w d0 21115 beq.w loc_10350 ⋮ 21117 bne.s loc_102DA 21118 move.l #Obj_Bouncing_Ring,(a1)
sonic3k.asm lines 21102–21118 at 73de97c · upstream ↗ 35603 moveq #$20,d0 35604 cmp.w d0,d5 35605 blo.s loc_1A6A6 35606 move.w d0,d5
sonic3k.asm lines 35603–35606 at 73de97c · upstream ↗ 35658 move.w #0,(Ring_count).wsonic3k.asm line 35658 at 73de97c · upstream ↗ Checked against the evidence by its author, an AI model, 2026-10-21.
Checked by a second AI model, 2026-10-21.
- ^Standing on flat ground, not on an object, not Super or Hyper, with no move_lock or infinite-inertia flag, with ground speed 0 after the left and right steps, and the floor under his center 12 px or more below his feet, Sonic turns to face right if last frame's right floor sensor met no block, or else left if the left one met none, and balances; otherwise Down crouches. Sonic 2 turned him only if the floor 6 px back the other way was also that far down.Codesonicretro/skdisasm · sonicretro/s2disasmrevised
How we know
22484 bne.w loc_112EA ; if yes, branch 22485 tst.w ground_vel(a0) ; is Sonic moving? 22486 bne.w loc_112EA ; if yes, branch ⋮ 22489 btst #Status_OnObj,status(a0) 22490 beq.w Sonic_Balance
sonic3k.asm lines 22480–22490 at 73de97c · upstream ↗ 22566Sonic_Balance: 22567 move.w x_pos(a0),d3 22568 bsr.w ChooseChkFloorEdge 22569 cmpi.w #$C,d1 22570 blt.w loc_11276 22571 tst.b (Super_Sonic_Knux_flag).w ; is Sonic Super/Hyper? 22572 bne.w loc_11250 ; if so, branch 22573 cmpi.b #3,next_tilt(a0) 22574 bne.s loc_111F6 22575 btst #Status_Facing,status(a0) 22576 bne.s loc_111CE
sonic3k.asm lines 22566–22576 at 73de97c · upstream ↗ 22587loc_111CE: ⋮ 22591 bclr #Status_Facing,status(a0)
sonic3k.asm lines 22587–22591 at 73de97c · upstream ↗ 22602loc_111F6: 22603 cmpi.b #3,tilt(a0) 22604 bne.s loc_11276 22605 btst #Status_Facing,status(a0) 22606 beq.s loc_11228 ⋮ 22617loc_11228: 22618 bset #Status_Facing,status(a0)
sonic3k.asm lines 22602–22618 at 73de97c · upstream ↗ 22035 move.b (Primary_Angle).w,next_tilt(a0) 22036 move.b (Secondary_Angle).w,tilt(a0)
sonic3k.asm lines 22035–22036 at 73de97c · upstream ↗ 36717+ move.b #AniIDSonAni_Balance3,anim(a0) ; set Sonic's animation to "Balance3" ⋮ 36719 subq.w #6,d3 36720 jsr (ChkFloorEdge_Part2).l 36721 cmpi.w #$C,d1 36722 blt.w Obj01_ResetScr ⋮ 36724 bclr #status.player.x_flip,status(a0)
s2.asm lines 36717–36724 at 4ef457c · upstream ↗ 22467 tst.b status_secondary(a0) ; is bit 7 set? (Infinite inertia) 22468 bmi.w loc_11332 ; if so, branch 22469 tst.w move_lock(a0) 22470 bne.w loc_112EA
sonic3k.asm lines 22467–22470 at 73de97c · upstream ↗ 20343loc_1228A: ⋮ 20347 bclr #Status_Facing,status(a0)
s3.asm lines 20343–20347 at 73de97c · upstream ↗ Checked against the evidence by its author, an AI model, 2026-10-26.
Revised after a check by a second AI model, 2026-10-26.
- ^Unlike Sonic 1 and Sonic 2, a standing player slides on a slope whose push, sine ×
$20, is at least$D; the walking and rolling factors stay$20and$50.Codesonicretro/skdisasm · sonicretro/s2disasm · sonicretro/s1disasmrevisedHow we know
23868 muls.w #$20,d0 23869 asr.l #8,d0 23870 tst.w ground_vel(a0) 23871 beq.s loc_11DDC ⋮ 23875 add.w d0,ground_vel(a0) ⋮ 23882 add.w d0,ground_vel(a0) ⋮ 23888loc_11DDC: 23889 move.w d0,d1 23890 bpl.s loc_11DE2 23891 neg.w d1 ⋮ 23893loc_11DE2: 23894 cmpi.w #$D,d1 ⋮
sonic3k.asm lines 23866–23896 at 73de97c · upstream ↗ 23914 muls.w #$50,d0sonic3k.asm line 23914 at 73de97c · upstream ↗ 37763 tst.w inertia(a0) 37764 beq.s return_1ADCA
s2.asm lines 37763–37764 at 4ef457c · upstream ↗ 1334 tst.w obInertia(a0) ; check Sonic's ground speed 1335 beq.s .return ; if he's standing still, branch
_incObj/01 Sonic.asm lines 1334–1335 at 15dfa3a · upstream ↗ Checked against the evidence by its author, an AI model, 2026-10-21.
Revised after a check by a second AI model, 2026-10-21.
- ^Below
$280ground speed on a steep slope the player now slips, a$80push along the slope and a 30-frame d-pad lock, and falls off only near walls and ceilings; Sonic 1 and 2 dropped him from any slope past 45°.Codesonicretro/skdisasm · sonicretro/s2disasm · sonicretro/s1disasmrevisedHow we know
23953 move.b angle(a0),d0 23954 addi.b #$18,d0 23955 cmpi.b #$30,d0 23956 blo.s locret_11E6E ⋮ 23962 cmpi.w #$280,d0 23963 bhs.s locret_11E6E 23964 move.w #30,move_lock(a0) 23965 move.b angle(a0),d0 23966 addi.b #$30,d0 23967 cmpi.b #$60,d0 23968 blo.s loc_11E70 23969 bset #Status_InAir,status(a0) ⋮
sonic3k.asm lines 23953–23983 at 73de97c · upstream ↗ 37833 addi.b #$20,d0 37834 andi.b #$C0,d0 ⋮ 37839 clr.w inertia(a0) 37840 bset #status.player.in_air,status(a0)
s2.asm lines 37832–37841 at 4ef457c · upstream ↗ 1413 addi.b #$20,d0 ; rotate it by 45 degrees 1414 andi.b #$C0,d0 ; snap to nearest multiple of 90 degrees ⋮ 1425 clr.w obInertia(a0) ; clear ground speed 1426 bset #status_in_air_bit,obStatus(a0) ; set in-air flag to detach Sonic from wall
_incObj/01 Sonic.asm lines 1412–1427 at 15dfa3a · upstream ↗ Checked against the evidence by its author, an AI model, 2026-10-21.
Revised after a check by a second AI model, 2026-10-21.
- ^ abTails flies for 480 frames, a count of 240 that drops every other frame; flying adds
$8gravity a frame, and while time remains each press lifts him$20a frame for up to 30 frames, until he rises faster than 1 px/frame.Codesonicretro/skdisasmHow we know
28704 move.b #1,double_jump_flag(a0) 28705 move.b #(8*60)/2,double_jump_property(a0)
sonic3k.asm lines 28703–28705 at 73de97c · upstream ↗ 27634 andi.b #1,d0 27635 beq.s loc_14836 27636 tst.b double_jump_property(a0) 27637 beq.s loc_14836 27638 subq.b #1,double_jump_property(a0) ⋮ 27643 cmpi.w #-$100,y_vel(a0) 27644 blt.s loc_14858 27645 subi.w #$20,y_vel(a0) 27646 addq.b #1,double_jump_flag(a0) 27647 cmpi.b #$20,double_jump_flag(a0) ⋮ 27661 cmpi.w #-$100,y_vel(a0) ⋮ 27663 tst.b double_jump_property(a0) ⋮
sonic3k.asm lines 27632–27674 at 73de97c · upstream ↗ 27614 jsr (MoveSprite_TestGravity2).lsonic3k.asm lines 27610–27614 at 73de97c · upstream ↗ Checked against the evidence by its author, an AI model, 2026-10-21.
Checked by a second AI model, 2026-10-21.
- ^Knuckles's glide starts at 4 px/frame and gains
$4a frame to a cap of 24 px/frame, and its fall settles near 0.5 px/frame,$20added below$80and taken above.Codesonicretro/skdisasmrevisedHow we know
32606 addi.w #$200,y_vel(a0) 32607 bpl.s loc_17898 32608 move.w #0,y_vel(a0) ⋮ 32610loc_17898: 32611 moveq #0,d1 32612 move.w #$400,d0 32613 move.w d0,ground_vel(a0)
sonic3k.asm lines 32600–32613 at 73de97c · upstream ↗ 31643 cmpi.w #$400,d0 31644 bhs.s .mediumSpeed ⋮ 31648 addq.w #8,d0 ⋮ 31654 cmpi.w #$1800,d0 31655 bhs.s .applySpeed ⋮ 31663 addq.w #4,d0
sonic3k.asm lines 31642–31663 at 73de97c · upstream ↗ 31723 cmpi.w #$80,y_vel(a0) 31724 blt.s .fallingSlow 31725 subi.w #$20,y_vel(a0) 31726 bra.s .fallingFast ⋮ 31731 addi.w #$20,y_vel(a0)
sonic3k.asm lines 31723–31731 at 73de97c · upstream ↗ 30749 andi.b #button_A_mask|button_B_mask|button_C_mask,d0 30750 bne.s .continueGliding ⋮ 30763 asr.w x_vel(a0) 30764 asr.w x_vel(a0)
sonic3k.asm lines 30748–30764 at 73de97c · upstream ↗ Checked against the evidence by its author, an AI model, 2026-10-21.
Revised after a check by a second AI model, 2026-10-21.
- ^Sonic & Knuckles's credits name Yuji Naka as producer and lead programmer, Hirokazu Yasuhara as director and lead game designer, Hisayoshi Yoshida and Takashi Iizuka as senior game designers, Takahiro Hamano and Masanobu Yamamoto as senior programmers, and Takashi Thomas Yuda as character designer. Sonic 3's name Hiroshi Nikaidoh where these name Hamano.Codesonicretro/skdisasm
How we know
122109 dc.b "PRODUCER",0 122110 even 122111byte_5B7AC: dc.b $37 122112 dc.b $18 122113 dc.b "YUJI NAKA",0 122114 even 122115byte_5B7B8: dc.b $47 122116 dc.b $1B 122117 dc.b "DIRECTOR",0 122118 even 122119byte_5B7C4: dc.b $49 122120 dc.b 8 ⋮
sonic3k.asm lines 122109–122169 at 73de97c · upstream ↗ 77570 dc.b " senior programmers",0 77571 even 77572 dc.w $688 77573 dc.b "HIROSHI NIKAIDOH",0 77574 even 77575 dc.w $980 77576 dc.b "MASANOBU YAMAMOTO",0
s3.asm lines 77570–77576 at 73de97c · upstream ↗ Checked against the evidence by its author, an AI model, 2026-10-26.
Checked by a second AI model, 2026-10-26.
- ^Yuji Naka said Knuckles came out of market research into American children's tastes: of eight candidate designs, Knuckles was the most popular.InterviewSega Magazine JP 1997, via Shmuplationsrevised
How we know
For the character of Knuckles, we relied a lot on market research about American kids’ taste. There were actually eight different candidates, but the most popular one was Knuckles with his dreadlocks.
Naka, on Sonic 3 · archived copy ↗ The quote matches our archived copy.
Revised after a check by a second AI model, 2026-10-26.
- ^Retro Gamer credits Knuckles's design to Takashi Yuda.InterviewRetro Gamer (GamesRadar), Sonic 3 at 30revised
How we know
The new playable character was Knuckles, designed by Takashi Yuda.
on the new playable character · archived copy ↗ The quote matches our archived copy.
Revised after a check by a second AI model, 2026-10-26.
- ^Takashi Iizuka said Knuckles's punch through rock let the team build routes only he could use, and his climbing and gliding brought vertical play to stages built for Sonic's horizontal one.InterviewRetro Gamer (GamesRadar), Sonic 3 at 30
How we know
Knuckles' ability to punch through rocks allowed us to create routes that only he could use," Iizuka explains. "Sonic's playstyle was horizontal, while Knuckles' climbing and gliding allowed us to bring in vertical play.
Iizuka on Knuckles's abilities · archived copy ↗ The quote matches our archived copy.
Checked by a second AI model, 2026-10-26.
- ^Yuji Naka said Sonic 3 was first built from late January 1993 for Sega's SVP chip, with isometric 3D graphics, and that the team dropped that work in June 1993 when the chip looked unlikely to be finished by the end of the year, restarting with six months left.InterviewSega Magazine JP 1997, via Shmuplations
How we know
Up till about June of 1993, the Sonic 3 development included the SVP. It featured isometric 3D graphics, and you could rotate and turn the game field. … The development began in late January of 1993 … Unfortunately, in June we realized that development of the SVP chip probably wouldn’t be finished by the end of the year. So we abandoned all the programming and work we’d done up to then. In the remaining 6 months we had for Sonic 3, we had to start entirely from zero and re-do everything.
Naka, on Sonic 3 · archived copy ↗ The quote matches our archived copy.
Checked by a second AI model, 2026-10-26.
- ^Takashi Iizuka gave Retro Gamer a different reason for dropping the SVP chip: the work was a research experiment in moving Sonic in 3D, and since the chip handled only about as many polygons as Virtua Racing, the team judged it not a good fit for a Sonic game.InterviewRetro Gamer (GamesRadar), Sonic 3 at 30revised
How we know
Support for the SVP chip was nothing more than a research experiment to see if we could get Sonic moving in 3D. In the end we found that it could only handle a polygon count similar to Virtua Racing, so we decided that it wasn't a good fit for a Sonic game.
on the SVP chip and the deadline · archived copy ↗ The quote matches our archived copy.
Revised after a check by a second AI model, 2026-10-26.
- ^Roger Hector, head of Sega Technical Institute, said the original Sonic 3 was so large in scope that it was split in half across two games, since it could not all fit in one.InterviewRoger Hector interview, 2005
How we know
The original Sonic 3 game was very aggressive in its scope. Massive really. So after getting started working on it, it was decided to split it in half, and spread the design across two games. This was good as there was no way all of it would fit in one game.
answer on the split · archived copy ↗ Roger Hector: Director of STI
page title · archived copy ↗ The quote matches our archived copy.
Checked by a second AI model, 2026-10-26.
- ^Mean Machines Sega's March 1994 review of Sonic 3 reported plans for a 24-megabit deluxe edition with extra levels, and possibly a plug-through cartridge for the 16-megabit Sonic 3 that would also work with Sonic 1 and 2.MagazineMMS 17, Mar 1994
How we know
Sonic plan a deluxe 24-Meg edition of the game, with extra levels and enhanced play. There may well be an upgrade for the 16-meg edition, a plug through cart with two ends, which will also work with your Sonic 1 and 2 carts, to create extra levels.
p. 49, "Cart Spec" box (archive.org page n48) · archived copy ↗ Checked against the evidence by its author, an AI model, 2026-10-26.
Checked by a second AI model, 2026-10-26.
- ^Retro Gamer reports that the split moved Flying Battery Zone, planned between Carnival Night and IceCap, to become Sonic & Knuckles's second zone.InterviewRetro Gamer (GamesRadar), Sonic 3 at 30revised
How we know
Flying Battery Zone was originally positioned between Carnival Night Zone and Ice Cap Zone, but was moved to become the second stage of Sonic & Knuckles instead.
on the split's effects · archived copy ↗ The quote matches our archived copy.
Revised after a check by a second AI model, 2026-10-26.
- ^Takashi Iizuka said he didn't think the split added or moved other stages, but it changed some: Launch Base, now Sonic 3's last zone, got an extra boss, Big Arms, and Mushroom Hill, now Sonic & Knuckles's first, was made easier than planned.InterviewRetro Gamer (GamesRadar), Sonic 3 at 30revised
How we know
I don't think there were any other stages that were added or moved, but we did make some spec changes, … The Launch Base boss was an Eggman boss as usual, but splitting the game made it the last stage of Sonic 3, so we added Big Arms. Mushroom Hill became the first stage of Sonic & Knuckles, so we readjusted the difficulty to make it easier than originally planned.
Iizuka on the split's effects · archived copy ↗ The quote matches our archived copy.
Revised after a check by a second AI model, 2026-10-26.
- ^Game Informer reports that the lock-on slot reads the ID of the cartridge on top, and that most other games bring up Sonic 3's and Sonic & Knuckles's blue sphere special stages.WebGame Informer, Sonic 3 splitrevised
How we know
The lock-on slot of Sonic & Knuckles would read the ID of whatever cartridge was put on it, so the team tried to have some fun with it. … For the vast majority of games, the result is the special "blue sphere" stages from Sonic 3 and Sonic & Knuckles.
"Stacking Other Games on Sonic & Knuckles" · archived copy ↗ The quote matches our archived copy.
Revised after a check by a second AI model, 2026-10-26.
- ^Sonic 3's credits name Brad Buxer, Bobby Brooks, Darryl Ross, Geoff Grace, Doug Grigsby III, and Scirocco as music composers, beside the Sega Sound Team, which includes Jun Senoue. Sonic & Knuckles alone credits Howard Drossin as its composer; locked onto Sonic 3, its credits list all seven.Codesonicretro/skdisasm
How we know
77645 dc.b "music composers",0 77646 even 77647 dc.w $694 77648 dc.b "BRAD BUXER",0 77649 even 77650 dc.w $98E 77651 dc.b "BOBBY BROOKS",0 77652 even 77653word_40EF8: dc.w 3-1 77654 dc.w $498 77655 dc.b "music composers",0 77656 even ⋮
s3.asm lines 77645–77671 at 73de97c · upstream ↗ 77705 dc.b "sega sound team",0 77706 even 77707 dc.w $68C 77708 dc.b "MASAYUKI NAGAO",0 77709 even 77710 dc.w $994 77711 dc.b "J UN SENOUE",0
s3.asm lines 77705–77711 at 73de97c · upstream ↗ 121578 moveq #0,d2 121579 tst.w (SK_alone_flag).w 121580 beq.s loc_5B238 121581 moveq #8,d2 ⋮ 121583loc_5B238: 121584 add.w (_unkFAAE).w,d2 121585 movea.l off_5B284(pc,d2.w),a1
sonic3k.asm lines 121578–121585 at 73de97c · upstream ↗ 121612off_5B284: 121613 dc.l CreditsText_Part1 121614 dc.l CreditsText_Part2 121615 dc.l CreditsText_Part1_SK 121616 dc.l CreditsText_Part2_SK
sonic3k.asm lines 121612–121616 at 73de97c · upstream ↗ 967SK_alone_flag ds.w 1 ; -1 if Sonic 3 isn't locked onsonic3k.constants.asm line 967 at 73de97c · upstream ↗ 122269 dc.b "MUSIC COMPOSERS",0 122270 even 122271byte_5BA08: dc.b 4 122272 dc.b $E 122273 dc.b "HOWARD DROSSIN",0 122274 even 122275byte_5BA1A: dc.b $14 122276 dc.b $D 122277 dc.b "SEGA SOUND TEAM",0
sonic3k.asm lines 122269–122277 at 73de97c · upstream ↗ 122663 dc.b "MUSIC COMPOSERS",0 122664 even 122665byte_5BFC0: dc.b 4 122666 dc.b $16 122667 dc.b "BRAD BUXER",0 122668 even 122669byte_5BFCE: dc.b 5 122670 dc.b $12 122671 dc.b "BOBBY BROOKS",0 122672 even 122673byte_5BFDE: dc.b 6 122674 dc.b $14 ⋮
sonic3k.asm lines 122663–122695 at 73de97c · upstream ↗ Checked against the evidence by its author, an AI model, 2026-10-26.
Checked by a second AI model, 2026-10-26.
- ^ abRoger Hector said Michael Jackson was brought in to compose the game's music and that his work was dropped at the end of development, after his scandals became public.InterviewRoger Hector interview, 2005revised
How we know
Michael Jackson was originally brought in to compose all the music for the game, but at the very end, his work was dropped after his scandals became public. This caused a lot of problems and required a lot of reworking.
answer on his favorite project · archived copy ↗ The quote matches our archived copy.
Revised after a check by a second AI model, 2026-10-26.
- ^ abVGC reports that Jackson isn't credited, that his musical director Brad Buxer has said Jackson worked on the soundtrack for four weeks in 1993, that Sega has never confirmed it, and that former Sega executives, Tom Kalinske among them, have said any part he had was without their knowledge. Digital Spy's 2014 retrospective says reports suggest he left over the Mega Drive's limits on music.WebVGC, Sonic Origins soundtrack · Digital Spy, Sonic 3 retrospectiverevised
How we know
Sonic 3’s soundtrack is infamous because it’s widely believed that some of the tracks were composed by Michael Jackson, who wasn’t credited in the final game. Jackson’s musical director Brad Buxer has claimed that Jackson worked on the soundtrack for four weeks in 1993, but Sega has never officially confirmed it … notable Sega executives including former Sega of America president Tom Kalinske have said that if he was involved it was without their knowledge.
background · archived copy ↗ reports suggest that the King of Pop exited the project due to the limitations of the Mega Drive's musical output.
trivia paragraph · archived copy ↗ The quote matches our archived copy.
Revised after a check by a second AI model, 2026-10-26.
- ^Electronic Gaming Monthly's April 1995 "EGM 50", its Review Crew's ranking of the past year's highest-rated games, put Sonic 3 at number 1.MagazineEGM 69, Apr 1995
How we know
the EGM 50 details the Review Crew’s rankings of the highest-rated softs from the past year.
The EGM 50 · archived copy ↗ RANKING: #1 Sega Genesis Sonic 3
The EGM 50, number 1 · archived copy ↗ The quote matches our archived copy.
Checked by a second AI model, 2026-10-26.
- ^GamePro's reviewer, The Unknown Gamer, scored Sonic 3 5 of 5 for graphics, control, and fun and 4 for sound, found the acts more linear than the first games', and called it "another spectacular game".MagazineGamePro 56, Mar 1994revised
How we know
Graphics Sound Control FunFactor Challenge INT. 5.0 4.0 5.0 5.0 Intermediate
p. 42, ProReview score box (archive.org page n43) · archived copy ↗ Sonic 3 proves that you can teach an old hedgehog new and exciting tricks. Take that old Sonic magic, add fun new variations, and you have another spectacular game.
p. 42, ProFile · archived copy ↗ The Acts have multiple pathways, but they are more linear than those in the first games.
p. 42 · archived copy ↗ Checked against the evidence by its author, an AI model, 2026-10-26.
Revised after a check by a second AI model, 2026-10-26.
- ^ abMean Machines Sega scored Sonic 3 94% overall, with 95 for playability; its reviewer Gus wrote that he had said Sonic 3 "had to be something special" and that it was, and the box faulted it for having no difficulty settings and for being partly finishable within a week.MagazineMMS 17, Mar 1994
How we know
OVERALL 94
p. 49, score boxes (archive.org page n48) · archived copy ↗ As I said in last month's preview, Sonic 3 had to be something special. It definitely is.
p. 49, Gus's comment · archived copy ↗ Sonic really should have difficulty settings.
p. 49, Presentation box · archived copy ↗ You can partially complete the game (without emeralds) within a week
p. 49, Lastability box · archived copy ↗ Checked against the evidence by its author, an AI model, 2026-10-26.
Checked by a second AI model, 2026-10-26.
- ^ abSega Power scored Sonic 3 90%; its verdict found "no radical changes to the gameplan" but called it a must-buy for its size, graphics, imagination, and playability.MagazineSega Power 52, Mar 1994
How we know
No radical changes to the gameplan, but the sheer size, superb graphics, wealth of imagination and above all playability, guarantee Sonic 3 gold status. A 'must buy' title.
p. 30, Final Verdict (file 0030.webp) · archived copy ↗ Checked against the evidence by its author, an AI model, 2026-10-26.
Checked by a second AI model, 2026-10-26.
- ^ abMean Machines Sega scored Sonic & Knuckles 85%. Gus found its likeness to Sonic 3 "almost disturbing", and Steve Merrett judged it "every bit as good as Sonic 3" but "more of the same"; the box praised the lock-on for putting life into games already bought.MagazineMMS 25, Nov 1994 · Retro Gamer (GamesRadar), Sonic 3 at 30
How we know
OVERALL 85
p. 72, score boxes (archive.org page n71) · archived copy ↗ The similarity to the other Sonic games is obvious, and the feeling of Deja vu with Sonic 3 is almost disturbing.
p. 72, Gus's comment · archived copy ↗ Sonic and Knuckles is every bit as good as Sonic 3, but it is just more of the same
p. 72, Steve's comment · archived copy ↗ The plug-through facility injects some life into games already bought.
p. 72, VFM box · archived copy ↗ In Mean Machines Sega, Steve Merrett felt it was
"New shoes" section · archived copy ↗ Checked against the evidence by its author, an AI model, 2026-10-26.
Checked by a second AI model, 2026-10-26.
- ^VideoGames named Earthworm Jim the best Genesis game of 1994 and gave Sonic & Knuckles one of its two honorable mentions, with Contra: Hard Corps.MagazineVideoGames Best of '94
How we know
without a doubt the best Genesis game of 1 994. Honorable Mention CONTRA: HARD CORPS (Konami) SONIC & KNUCKLES (Sega)
Best of '94, Genesis · archived copy ↗ The quote matches our archived copy.
Checked by a second AI model, 2026-10-26.
- ^Later reviews single out the saves and Knuckles. GameSpot's Frank Provo called the six save slots Sonic 3's most welcome new feature in 2007, and Digital Spy's Mark Langshaw wrote in 2014 that it was the series' first game with saves but that its greatest contribution was Knuckles.WebGameSpot, Sonic 3 review · Digital Spy, Sonic 3 retrospective
How we know
Without a doubt, the most welcome new feature in Sonic 3 is the one that doesn't have anything to do with gameplay: the six save slots that record your progress.
review body · archived copy ↗ The game gave players the option to save their progress for the first time in the series, but its greatest contribution to the franchise was the introduction of Knuckles.
retrospective body · archived copy ↗ The quote matches our archived copy.
Checked by a second AI model, 2026-10-26.
- ^Sonic 3 and Sonic & Knuckles came to the PC in 1997 as Sonic & Knuckles Collection, playable apart or together, with MIDI music that replaced some tracks. They came to the Saturn in Sonic Jam the same year, and emulated versions were part of Sega's compilations until 2010.InterviewRetro Gamer (GamesRadar), Sonic 3 at 30revised
How we know
Sonic 3 and Sonic & Knuckles later made their way to PC in 1997 as part of Sonic & Knuckles Collection, which offers the ability to play either game individually or both together. This version features MIDI music and replaces some of the tracks attributed to Michael Jackson's team with tunes that were present in a prototype build of the Mega Drive game. The games arrived on the Saturn as part of Sonic Jam the same year with no substantial changes, and emulated Mega Drive versions were a staple of Sega's compilations until 2010, when re-releases dried up.
"New shoes" section · archived copy ↗ The quote matches our archived copy.
Revised after a check by a second AI model, 2026-10-26.
- ^Sonic Origins (2022) brought back Sonic 3 & Knuckles as one game, Retro Gamer reports, and VGC reports Sega saying in a livestream that it couldn't use "all the original sounds" of the Genesis game and that Jun Senoue had adapted the music composed in 1993.InterviewRetro Gamer (GamesRadar), Sonic 3 at 30 · VGC, Sonic Origins soundtrackrevised
How we know
Sonic 3 & Knuckles finally returned in combined and remastered form as part of the Sonic Origins compilation in 2022.
closing section · archived copy ↗ While unfortunately we can’t use all the original sounds from the Sega Genesis version of the game, Jun Senoue has been working really hard to adapt the original music that was composed in 1993 for Sonic Origins.
Chrzanowski in an official Sonic livestream · archived copy ↗ The quote matches our archived copy.
Revised after a check by a second AI model, 2026-10-26.
- ^Takashi Iizuka said he had wished to sell Sonic 3 and Sonic & Knuckles as one complete game, and was happy that Sonic Origins did.InterviewRetro Gamer (GamesRadar), Sonic 3 at 30revised
How we know
I do wish we had been able to sell Sonic 3 and Sonic & Knuckles as one complete game. So I was happy that we were able to accomplish that with Sonic Origins last year,
Iizuka, closing section · archived copy ↗ The quote matches our archived copy.
Revised after a check by a second AI model, 2026-10-26.
Sources
Code
- Sonic Retro contributors. 2026. “skdisasm: Sonic 3 & Knuckles disassembly (sonicretro/skdisasm).” Commit 73de97c. sonicretro/skdisasm @ 73de97c · licence, all uses
- Sonic Retro contributors. 2026. “s1disasm: Sonic the Hedgehog (16-bit) disassembly (sonicretro/s1disasm).” Commit 15dfa3a. sonicretro/s1disasm @ 15dfa3a · licence, all uses
- Sonic Retro contributors. 2026. “s2disasm: Sonic the Hedgehog 2 (16-bit) disassembly (sonicretro/s2disasm).” Commit 4ef457c. sonicretro/s2disasm @ 4ef457c · licence, all uses
Primary
- Thorpe, Nick. 2024. “30 years later, Sonic the Hedgehog 3 is still a stone-cold classic.” Future plc (Retro Gamer, published on GamesRadar+). original · archived · licence, all uses
- America, Sega of. 1994. “Sonic & Knuckles instruction manual (US, Genesis).” Sega of America. original · archived · licence, all uses
- America, Sega of. 1994. “Sonic The Hedgehog 3 instruction manual (US, Genesis).” Sega of America. original · archived · licence, all uses
- staff, Sega Magazine (Japan) and Shmuplations (translation). 1997. “Sonic Team story (ソニックチーム物語).” SoftBank Creative; translation by Shmuplations. original · archived · licence, all uses
- Naka, Yuji and GameSpy staff. 2005. “Sega's Yuji Naka Talks! (page 4).” GameSpy (IGN Entertainment). original · archived · licence, all uses
- Hector, Roger and HXC (interviewer). 2005. “Roger Hector: Director of STI interviews.” EmulationZone / Simon Wai's Sonic 2 Beta. original · archived · licence, all uses
Secondary
- staff, Sega Visions. 1994. “Sega Visions, issue 17 (February/March 1994).” Sega Visions, issue 17. Sega of America. original · archived · licence, all uses
- Gus and Mean Machines Sega staff. 1994. “Mean Machines Sega, issue 17 (March 1994).” Mean Machines Sega, issue 17. EMAP. original · archived · licence, all uses
- staff, Beep! MegaDrive. 1994. “Beep! MegaDrive, June 1994.” Beep! MegaDrive, June 1994 issue. SoftBank. original · archived · licence, all uses
- staff, Sega Visions. 1994. “Sega Visions, issue 21 (October/November 1994).” Sega Visions, issue 21. Sega of America. original · archived · licence, all uses
- staff, Beep! MegaDrive. 1994. “Beep! MegaDrive, November 1994.” Beep! MegaDrive, November 1994 issue. SoftBank. original · archived · licence, all uses
- Shea, Brian. 2016. “How Sonic 3 Became Two Separate Games.” Game Informer. original · archived · licence, all uses
- Horowitz, Ken. 2007. “Developer's Den: Sega Technical Institute.” Sega-16. original · archived · licence, all uses
- staff, Electronic Gaming Monthly. 1994. “Electronic Gaming Monthly, no. 56 (March 1994).” Electronic Gaming Monthly, vol. 7 no. 3 (issue 56). Ziff Davis. original · archived · licence, all uses
- staff, Sega Power. 1994. “Sega Power, issue 54 (May 1994).” Sega Power, issue 54. Future Publishing. original · archived · licence, all uses
- Parish, Jeremy. 2013. “The 10 Best Genesis/Mega Drive and Top 5 Sega CD Games.” USgamer (Eurogamer/Gamer Network). original · archived · licence, all uses
- Whitehead, Dan. 2009. “SEGA Vintage Collection review.” Eurogamer (Gamer Network). original · archived · licence, all uses
- Scullion, Chris. 2022. “Sonic 3 & Knuckles won't have its original soundtrack in Sonic Origins.” Video Games Chronicle. original · archived · licence, all uses
- Langshaw, Mark. 2014. “Sonic the Hedgehog 3 retrospective: Sega mascot's finest outing.” Digital Spy (Hearst). original · archived · licence, all uses
- staff, Electronic Gaming Monthly. 1995. “Electronic Gaming Monthly, no. 69 (April 1995): The EGM 50.” Electronic Gaming Monthly, issue 69. Ziff Davis. original · archived · licence, all uses
- Gamer, The Unknown. 1994. “GamePro, vol. 6 no. 3 (March 1994).” GamePro, vol. 6 no. 3 (issue 56). IDG Communications. original · archived · licence, all uses
- staff, Sega Power. 1994. “Sega Power, issue 52 (March 1994).” Sega Power, issue 52. Future Publishing. original · archived · licence, all uses
- Gus, Steve, and Mean Machines Sega staff. 1994. “Mean Machines Sega, issue 25 (November 1994).” Mean Machines Sega, issue 25. EMAP. original · archived · licence, all uses
- staff, VideoGames. 1995. “VideoGames: The Ultimate Gaming Magazine, issue 74 (March 1995): Best of '94.” VideoGames: The Ultimate Gaming Magazine, issue 74. Larry Flynt Publications. original · archived · licence, all uses
- Provo, Frank. 2007. “Sonic the Hedgehog 3 Review (Virtual Console).” GameSpot (CBS Interactive). original · archived · licence, all uses