Super Mario Bros. 2 (Super Mario Bros. 2, Discombobulated, Xkeeper0/smb2)

Super Mario Bros. 2 keeps speeds as 4.4 fixed point; ApplyPlayerPhysics takes whole pixels from a speed's upper nibble. smb2/velocity-format

About: Super Mario Bros. 2 Gravity

PlayerStartJump first checks quicksand: sunk with QuicksandDepth 2 or more, the player takes off at JumpHeightQuicksand, $E0 for all four (quicksand), and the table is skipped. Otherwise it picks the take-off speed from the character's table by three bits: running (horizontal speed of $08 or more), a charged crouch (CrouchJumpTimer at $3C), and holding an item. A charged jump clears the running bit. smb2/jump-start

About: Super Mario Bros. 2 Jump

{
 "runSpeed": 8,
 "chargeFrames": 60
}

Cited by: Super Mario Bros. 2

Measured in Mesen (MesenCE 2.2.1) from power-on, on the floor at the bottom of 1-1's first area (probes/super-mario-bros-2/movement.mjs), empty-handed Mario's jumps leave the ground at -5 standing, -5.625 running, and -6.5 px/frame from a charged crouch, and each frame adds 0.25 px/frame with A held and 0.4375 without: MarioStats' $B0, $A6, and $98, and its gravities $04 and $07. With an item, see carry-stats. smb2/mario-stats

About: Super Mario Bros. 2 Jump

{
 "still": -80,
 "running": -90,
 "charged": -104,
 "gravity": 7,
 "gravityHeld": 4
}

Cited by: Super Mario Bros. 2

Luigi takes off far slower but falls under a far lighter gravity. Measured in Mesen (MesenCE 2.2.1) from power-on, on the floor at the bottom of 1-1's first area, empty-handed, his jumps leave the ground at -2.625 standing, -3 running, and -3.4375 px/frame charged, and each frame adds 0.0625 px/frame with A held and 0.125 without: LuigiStats' $D6, $D0, and $C9, and its gravities $01 and $02. With an item, see carry-stats. smb2/luigi-stats

About: Super Mario Bros. 2 Jump

{
 "still": -42,
 "running": -48,
 "charged": -55,
 "gravity": 2,
 "gravityHeld": 1
}

Cited by: Super Mario Bros. 2

PlayerGravity adds the character's lighter gravity on any frame the jump button is held and the heavier one otherwise, and adds none once a fall has reached $39 (3.5625 px/frame). The last add can carry the fall past that, up to $3F (3.9375 px/frame) under a gravity of $07. Two branches come first: sunk in quicksand (QuicksandDepth 2 or more), the routine adds GravityQuicksand, $08 for all four (quicksand), at any speed; and while the Princess floats, it sets her speed outright from FloatingYVelocity and adds nothing (float). smb2/gravity

About: Super Mario Bros. 2 Gravity

{
 "fallStop": 57,
 "maxFall": 63
}

Cited by: Super Mario Bros. 2

The Princess's Floating Time is $3C; the other three have 0. With the button held once her rise has slowed to -$04 or less, each frame sets her vertical speed from FloatingYVelocity, cycling up, still, down, still, until the timer runs out. Letting go ends the float for that jump. Measured in Mesen (MesenCE 2.2.1) from power-on, on the floor at the bottom of 1-1's first area, a jump with A held floats for 60 frames, holding each speed of the cycle for 8 frames, and then falls. smb2/float

About: Super Mario Bros. 2 Flight

{
 "frames": 60,
 "cycle": [
  -4,
  0,
  4,
  0
 ]
}

Cited by: Flight, Super Mario Bros. 2

Holding B raises the top speed by half: running right with nothing carried, from $18 to $24 (1.5 to 2.25 px/frame). Measured in Mesen (MesenCE 2.2.1) from power-on, on the floor at the bottom of 1-1's first area, all four characters run right at 1.5 px/frame and, with B, 2.25 px/frame. smb2/run-cap

About: Super Mario Bros. 2 Running

{
 "walk": 24,
 "run": 36
}

Cited by: Super Mario Bros. 2

The run button's half is added to whatever cap applies, the carrying speed (carry-speed) or quicksand's $04 as well as the unladen $18. To the left the cap is negative, and halving it with the carry set rounds it away from zero: a cap of $EB to the left becomes $E0, where $15 to the right becomes $1F. smb2/run-cap-rules

About: Super Mario Bros. 2 Running

Health is $0F for one mark of the life meter and $10 more for each further mark, up to $3F for four. A hit takes $10, one mark, and sets DamageInvulnTime to $7F, during which DamagePlayer returns at once; the timer drops every frame. If the health left is $10 or more, two marks or more, the hit also launches the player upward at $C0 and sideways at four times the screen distance from the enemy. A hit on the last mark (health under $10) stores no health and sets no invulnerability: it turns the enemy toward the player (for the types before Enemy_BeezoDiving), stuns it for $10 frames, sets the player's vertical speed to $C0 and PlayerStateTimer to $20, and jumps to KillPlayer, which sets the dying state and health to 0. A dying player holds still for those 32 frames, then rises at $C0 and falls back, gaining $02 a frame up to $39, and loses a life once below the screen. smb2/damage

About: Super Mario Bros. 2 Invincibility frames

{
 "frames": 127,
 "launchY": -64,
 "xPerPixel": 4
}

Cited by: Super Mario Bros. 2

Measured in Mesen (MesenCE 2.2.1) from power-on, on the floor at the bottom of 1-1's first area, empty-handed Toad's jumps leave the ground at -4.875 standing, -5.1875 running, and -6.5 px/frame charged, and fall under Mario's gravity, 0.25 px/frame a frame with A held and 0.4375 without: ToadStats' $B2, $AD, and $98, and $04 and $07. With an item, see carry-stats. smb2/toad-stats

About: Super Mario Bros. 2 Jump

{
 "still": -78,
 "running": -83,
 "charged": -104,
 "gravity": 7,
 "gravityHeld": 4
}

Cited by: Super Mario Bros. 2

Measured in Mesen (MesenCE 2.2.1) from power-on, on the floor at the bottom of 1-1's first area, the empty-handed Princess's jumps leave the ground at -4.8125 standing, -5.25 running, and -6.5 px/frame charged, and fall under Mario's gravity, 0.25 px/frame a frame with A held and 0.4375 without, apart from her float (float): PrincessStats' $B3, $AC, and $98, and $04 and $07. With an item, see carry-stats. smb2/princess-stats

About: Super Mario Bros. 2 Jump

{
 "still": -77,
 "running": -84,
 "charged": -104,
 "gravity": 7,
 "gravityHeld": 4
}

Cited by: Super Mario Bros. 2

Each character's stats table holds a second take-off for each kind of jump, used while carrying something. Standing, charged, and running, they are: Mario $B0, $98, $AA; Luigi $D6, $C9, $D4; Toad $B2, $98, $AD; the Princess $B3, $98, $B3. Against the empty-handed ones (mario-stats and the rest), an item lowers only the running jump: Mario's and Luigi's by $04, and the Princess's to her standing one; Toad's are unchanged. The same tables hold the ground caps, $18 empty-handed for all four, and carrying $18, $16, $1D, and $15 (carry-speed). smb2/carry-stats

About: Super Mario Bros. 2 Held item

Split from the four measured stats claims in the audit (2026-10-26), which keep only what the probe measured.

On ordinary ground, holding right adds $02 to the speed each frame, so a character reaches walking speed, $18 (1.5 px/frame), 12 frames from a standstill; with neither direction held the ground takes $03 a frame off the speed, to zero. Measured in Mesen (MesenCE 2.2.1) from power-on, on the floor at the bottom of 1-1's first area, each character reaches 1.5 px/frame in 12 frames from a standstill; letting go of everything at 2.25 px/frame drops the speed to the 1.5 cap at once, and friction stops the character 8 frames later. smb2/ground-speed

About: Super Mario Bros. 2 Running

{
 "accel": 2,
 "friction": 3,
 "toWalk": 12,
 "stop": 8
}

Cited by: Super Mario Bros. 2

Left and right push at the same $02 a frame in the air, and with neither held the air keeps the speed. Any push resets a crouch jump's charge (crouch-charge). Crouched on the ground, left and right do nothing, and the ground's friction slows the player. On ice the push comes on one frame in four and the friction on one in sixteen. smb2/ground-control

About: Super Mario Bros. 2 Running

What the player carries sets the ground cap: an enemy, a mushroom block, or a POW block uses the character's carrying speed (Mario $18, Luigi $16, Toad $1D, the Princess $15), and anything else (vegetables, shells, coins, bombs, rockets, keys, potions) the empty-handed $18. Sunk 4 pixels or more into quicksand, every character's cap is $04. B raises each by half (run-cap). smb2/carry-speed

About: Super Mario Bros. 2 Held item

{
 "mario": 24,
 "luigi": 22,
 "toad": 29,
 "princess": 21,
 "quicksand": 4
}

The manual's order is the carrying speeds' order; Mario's is the same as his empty-handed one, and Toad's is faster.

Cited by: Super Mario Bros. 2

Pulling something up, from the ground or off an enemy's or a block's top, holds a first pose for 6 frames, then steps through six more poses whose waits are the character's pick-up speeds, read from last to first: Mario's and Luigi's 7, 4, 1, 2, 4, 0, Toad's 2, 1, 1, 1, 1, 0, and the Princess's 12, 6, 2, 4, 6, 0, a wait of 0 lasting one frame. A small vegetable or dug sand takes Toad's waits whoever pulls it. Measured in Mesen (MesenCE 2.2.1) from power-on, pulling the large vegetable on the ledge in 1-1's first area, Mario and Luigi lift for 25 frames, Toad for 13, and the Princess for 37. smb2/pluck

About: Super Mario Bros. 2 Held item

{
 "frames": {
  "mario": 25,
  "luigi": 25,
  "toad": 13,
  "princess": 37
 }
}

The disassembly's comments number the pick-up speeds from the first byte, but the code reads them from the sixth. The two pulling poses ($08) take the last two bytes' waits.

Cited by: Super Mario Bros. 2

B throws what the player carries, unless it is sand from digging. A bomb, rocket, mushroom block, POW block, key, or potion needs room in the tile ahead; enemies, vegetables, shells, and coins fly at once. Those fly forward at $30 (3 px/frame), rising at $08 (0.5 px/frame) if the player was moving at $08 or more and falling at $18 if not. The others fly forward at $30 level if the player was moving, and if standing are set down 16 px ahead, falling at $18. smb2/throw

About: Super Mario Bros. 2 Held item

{
 "speed": 48,
 "rise": -8,
 "drop": 24,
 "moving": 8,
 "setDown": 16
}

Cited by: Super Mario Bros. 2

Holding Down on the ground charges the crouch jump for 60 frames, except on a flying carpet or in quicksand. Crouched on the ground, left and right do nothing; in the air, with Down held, they still steer. Let go of Down before then and the charge is lost; let go after and it is kept until left or right is pressed or the player jumps. smb2/crouch-charge

About: Super Mario Bros. 2 Jump

{
 "frames": 60
}

Cited by: Super Mario Bros. 2

Standing in quicksand sinks the player at $01 a frame, or $08 in the fast kind, and sinking 12 pixels into the next row of tiles kills them. Sunk 4 pixels or more, they jump at $E0 (2 px/frame), fall under gravity $08, run no faster than $04 (carry-speed), and can't charge a crouch jump. smb2/quicksand

{
 "slow": 1,
 "fast": 8,
 "jump": -32,
 "gravity": 8,
 "cap": 4
}

Cited by: Super Mario Bros. 2

On a vine, chain, or ladder the player climbs up at $F0 (1 px/frame), down at $20 (2 px/frame), and sideways at 1 px/frame. Holding up and down together reads past the end of the table, the byte $A5, and sends the player up at 5.6875 px/frame. Holding left and right together reads past the end of the sideways table too, again a byte $A5, the first of HandlePlayerState_Climbing, and sets the sideways speed to 5.6875 px/frame to the left. smb2/climbing

About: Super Mario Bros. 2 Climbing

{
 "up": -16,
 "down": 32,
 "side": 16,
 "zip": -91,
 "sideZip": -91
}

Cited by: Super Mario Bros. 2

Every eighth enemy defeated, counted as it falls off the screen, comes back as a heart 96 px above where it left; stray bullets and bosses don't count, and the count carries over deaths until the level ends. A heart adds one mark, up to the meter's length. smb2/hearts

About: Super Mario Bros. 2 Healing item

{
 "every": 8,
 "rise": 96
}

Cited by: Super Mario Bros. 2

A level has up to two Subspace mushrooms, each adding a mark to the life meter and refilling it. One taken stays taken, and the extra marks stay, through deaths until the level ends, a game over, or a warp, which set PlayerHealth to PlayerHealth_2_HP and PlayerMaxHealth to 0: a meter of two marks, both full. smb2/mushrooms

About: Super Mario Bros. 2 Health upgrade

{
 "perLevel": 2
}

Cited by: Super Mario Bros. 2

A thrown potion that lands makes a door in a puff of smoke, except in a vertical area, where only the smoke is left. Through the door, Subspace lasts 96 ticks of four frames, about 384 frames, and ends early if the player dies. Its grass gives coins on the level's first two visits that pull a coin, and small vegetables after. smb2/subspace

About: Super Mario Bros. 2 Area transition

{
 "ticks": 96,
 "frames": 384,
 "coinVisits": 2
}

The countdown's first tick falls 1 to 4 frames after entry, by the frame counter, so the stay is 381 to 384 frames.

Cited by: Super Mario Bros. 2

The fifth large vegetable pulled since the level began or the player last died is a stopwatch, and the count starts over. smb2/stopwatch

{
 "every": 5
}

Cited by: Super Mario Bros. 2

The Bonus Chance after a level spins three reels of eight positions, one coin a spin. Each position holds one of four symbols: a Snifit, a turnip, a star, or a cherry. Each reel steps every 4 frames, and A stops the leftmost still spinning. A cherry on the first reel wins a life, cherries on the first two win two, three cherries five, and three of another symbol one; lives stop at 255. Each reel holds one cherry. smb2/slot-machine

About: Super Mario Bros. 2 Bonus stage

{
 "reels": 3,
 "symbols": 8,
 "step": 4,
 "oneCherry": 1,
 "twoCherries": 2,
 "threeCherries": 5,
 "threeOther": 1
}

Cited by: Super Mario Bros. 2