Super Metroid

References

1. ^InsaneFirebat's sm_disassembly, assembled with asar for NTSC, equals Super Metroid (Japan, USA) (En,Ja) byte for byte.Code“Super Metroid (Japan, USA) (En,Ja)” · InsaneFirebat/sm_disassembly
   How we know

   In the cartridge (“Super Metroid (Japan, USA) (En,Ja)”): bank $90 $9E8B, SamusPhysicsConstants, the table most claims below read. We don't reproduce the bytes.

   19echo Success! This ROM matches vanilla Super Metroid
   

   34print "NTSC VERSION"
   35!FPS = 1
   36!SPF = 1
   

   Checked against the evidence by its author, an AI model, 2026-10-21.

   Checked by a second AI model, 2026-10-21.

   In the claim ledger

2. ^ abMake_Samus_Jump picks the take-off speed from a table by medium and the Hi-Jump Boots: 4.875 px/frame up in air, 1.75 in water, 2.75 in lava or acid, and 6, 2.5, and 3.5 with the boots. With the Speed Booster equipped, it adds Samus's extra run speed, the whole part halved.CodeInsaneFirebat/sm_disassembly
   How we know

   4198  .merge:
   ⋮
   4208  .hiJumpEquipped:
   

   4184  .normalGravity:
   ⋮
   4188  .submergedInWater:
   ⋮
   4195  .submergedInAcidLava:
   

   3995  .running:
   

   5124  .InitialYSpeeds_Jumping:
   ⋮
   5127  .InitialYSubSpeeds_Jumping:
   ⋮
   5130  .InitialYSpeeds_HiJumpJumping:
   

   Checked against the evidence by its author, an AI model, 2026-10-21.

   Checked by a second AI model, 2026-10-21.

   In the claim ledger

3. ^ abGravity is one constant in air, $1C00 subpixels (0.109375 px/frame²) every frame of a jump or fall, held button or not; water uses $0800 and lava or acid $0900. A fall stops gaining speed at 5 px/frame.CodeInsaneFirebat/sm_disassembly
   How we know

   5076  .YSubAccelerationInAir:
   5077; Samus Y subacceleration in air
   ⋮
   5081; Samus Y subacceleration in water
   

   4719  .notSubmerged:
   

   2984  .down:
   

   Checked against the evidence by its author, an AI model, 2026-10-21.

   Checked by a second AI model, 2026-10-21.

   In the claim ledger

4. ^In a normal or spin jump, letting go of jump while Samus rises sets her vertical speed to 0 and starts the fall at once; held, the rise lasts until gravity brings the speed to 0.CodeInsaneFirebat/sm_disassembly
   How we know

   2785  .jumping:
   

   LDA.B DP_Controller1Input AND.W JumpBinding BEQ + … + STZ.W SamusYSubSpeed STZ.W SamusYSpeed

   Checked against the evidence by its author, an AI model, 2026-10-21.

   Checked by a second AI model, 2026-10-21.

   In the claim ledger

5. ^Running accelerates Samus at 0.1875 px/frame² to 2.75 px/frame and slows her at 0.5 px/frame² once she lets go. Holding dash while running builds a separate extra run speed at 0.0625 px/frame², up to 2 px/frame, or 7 with the Speed Booster.CodeInsaneFirebat/sm_disassembly
   How we know

   5193; Used for Samus X base speed (due to general movement)
   ⋮
   5200    dd wordSwap($0030*!SPF*$100),wordSwap($02C0*!SPF*$100),           wordSwap($0080*!SPF*$100) ; 1: Running
   

   3982  .gravityContinued:
   ⋮
   3989  .checkDash:
   

   4040  .accelerating:
   

   5163  .XSubAccelerations_DashHeld:
   ⋮
   5166  .MaxXExtraRunSpeeds_SpeedBooster:
   ⋮
   5172  .MaxXExtraRunSpeeds_NoSpeedBooster:
   

   Checked against the evidence by its author, an AI model, 2026-10-21.

   Checked by a second AI model, 2026-10-21.

   In the claim ledger

6. ^ abAn enemy's touch sets SamusInvincibilityTimer to $60 (96), and Samus's contact check returns early while it is above 0. DecrementSamusHurtTimers_ClearActiveEnemyIndicesLists takes 1 from it, which the gameplay routine calls once per frame.CodeInsaneFirebat/sm_disassembly
   How we know

   LDA.L EnemyHeaders_damage,X JSL.L Suit_Damage_Division JSL.L Deal_A_Damage_to_Samus LDA.W #$0060 STA.W SamusInvincibilityTimer

   3392  .normalContact:
   

   2093DecrementSamusHurtTimers_ClearActiveEnemyIndicesLists:
   

   JSL.L DecrementSamusHurtTimers_ClearActiveEnemyIndicesLists

   Checked against the evidence by its author, an AI model, 2026-10-21.

   Checked by a second AI model, 2026-10-21.

   In the claim ledger

7. ^An enemy's touch sets a 5-frame SamusKnockbackTimer and a knockback direction from Samus's position against the enemy's. The knockback launches her at 5 px/frame up, or 2 in water, lava, or acid, and the upward knockback then moves her with the usual Y-speed code, gravity included.CodeInsaneFirebat/sm_disassembly
   How we know

   LDA.W #$0005 STA.W SamusKnockbackTimer LDY.W #$0000 LDX.W EnemyIndex LDA.W SamusXPosition SEC SBC.W Enemy.XPosition,X … STY.W KnockbackXDirection

   4352  .merge:
   

   5148  .InitialYSpeeds_Knockback:
   

   14262KnockbackMoement_Up:
   

   Checked against the evidence by its author, an AI model, 2026-10-21.

   Checked by a second AI model, 2026-10-21.

   In the claim ledger

8. ^A wall jump starts only from a spin jump or another wall jump. Once the spin animation reaches its wall-jump frames, with a direction held away from a wall or solid enemy within 8 px, a new jump press jumps off at 4.625 px/frame up, or 5.5 with the Hi-Jump Boots.CodeInsaneFirebat/sm_disassembly
   How we know

   4838WallJump_Check:
   

   4941  .wallJumpEligiblePressingLeft:
   

   4960  .wallJumpEligiblePressingRight:
   

   LDA.W SamusPhysicsConstants_MaximumDistanceFromWallForWallJump STA.B DP_Temp12 STZ.B DP_Temp14 JSR.W WallJump_Check

   5072  .MaximumDistanceFromWallForWallJump:
   5073; Maximum distance from wall for wall-jump
   

   5136  .InitialYSpeeds_WallJumping:
   ⋮
   5142  .InitialYSpeeds_HiJumpWallJumping:
   

   Checked against the evidence by its author, an AI model, 2026-10-21.

   Checked by a second AI model, 2026-10-21.

   In the claim ledger

9. ^In a spin jump in air with the Space Jump, a new jump press makes a fresh jump only while Samus falls at 2.5 px/frame or faster and below 5.CodeInsaneFirebat/sm_disassemblyrevised
   How we know

   5467SamusMovement_SpinJumping:
   5468; Handles space jump
   ⋮
   5513  .spaceJumpEligible:
   ⋮
   5526  .airPhysics:
   

   5056  .SpaceJumpMinimumYVelocityInAir:
   5057; Space jump minimum Y velocity in air * 100h
   ⋮
   5061; Space jump maximum Y velocity in air * 100h
   

   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.

   In the claim ledger

10. ^Super Metroid's running acceleration is Metroid's, $30/256 (0.1875) px/frame² in both, but its top speed rises from Metroid's 1.5 px/frame to 2.75. Metroid II, between them, has no acceleration and walks at 1.5 px/frame.Codenmikstas/metroid-disassembly · alex-west/M2RoS · InsaneFirebat/sm_disassembly
    How we know

    2245RunAccelerationTbl:
    2246LCCC0:  .byte $30           ;Accelerate right.
    

    5592LE37F:  lda #$18            ;
    5593LE381:  sta SamusHorzSpdMax       ;Set Samus maximum running speed.
    

    5648HorzAccelerate:
    5649LE3E5:  lda SamusHorzSpdMax
    5650    jsr Amul16       ; * 16
    ⋮
    5653    lda SamusHorzSpdMax
    5654    jsr Adiv16       ; / 16
    ⋮
    5658    lda HorzCntrLinear
    5659    clc
    5660    adc SamusHorzAccel
    

    4609            ; Normal walking speed (1.5 px/f)
    4610            ldh a, [frameCounter]
    4611            and $01
    4612            add $01
    4613            ld b, a
    ⋮
    4617    ldh a, [hSamusXPixel]
    4618    add b
    

    5200    dd wordSwap($0030*!SPF*$100),wordSwap($02C0*!SPF*$100),           wordSwap($0080*!SPF*$100) ; 1: Running
    

    Checked against the evidence by its author, an AI model, 2026-10-21.

    Checked by a second AI model, 2026-10-21.

    In the claim ledger

11. ^Super Metroid keeps Metroid's release cut, a release during the rise setting the vertical speed to 0, but drops Metroid's 32 px minimum rise. Metroid II, between them, holds a fixed rise for as long as A is held, up to a frame limit.Codenmikstas/metroid-disassembly · alex-west/M2RoS · InsaneFirebat/sm_disassembly
    How we know

    2705        CMP #$20
    2706        BCC +      ; branch if jumped less than 32 pixels upwards
    2707        BIT Joy1Status
    2708        BMI +      ; branch if JUMP button still pressed
    2709        JSR StopVertMovement        ;($D147)Stop jump (start falling).
    

    3884    ; Check if in linear portion of ascent
    3885    ld a, [samus_jumpArcCounter]
    3886    cp samus_jumpArrayBaseOffset
    3887    jr nc, .endIf_A
    3888        ; If so, check if A is pressed
    3889        ldh a, [hInputPressed]
    3890        bit PADB_A, a
    3891        jr z, .endIf_B
    ⋮
    3900        .endIf_B:
    3901        ; If A is not pressed, start falling portion of arc
    3902        ld a, samus_jumpArrayBaseOffset + $16 ;56
    3903        ld [samus_jumpArcCounter], a
    

    LDA.W SamusYDirection CMP.W #$0001 BNE .setFallingEnd LDA.B DP_Controller1Input AND.W JumpBinding BEQ + LDA.W SamusYSpeed BPL .setFallingEnd + STZ.W SamusYSubSpeed STZ.W SamusYSpeed

    Checked against the evidence by its author, an AI model, 2026-10-25.

    Checked by a second AI model, 2026-10-21.

    Checked by a second AI model, 2026-10-25.

    In the claim ledger

12. ^The three games build the high jump three ways. Metroid's High Jump Boots lower the jump's gravity from $18 to $12 and keep the take-off speed. Metroid II's Hi-Jump starts the held rise at a lower counter and adds 1 px/frame to it, 3 px/frame for up to 31 frames against 2 for up to 15. Super Metroid's Hi-Jump Boots raise the take-off speed from 4.875 to 6 px/frame, with gravity unchanged.Codenmikstas/metroid-disassembly · alex-west/M2RoS · InsaneFirebat/sm_disassemblyrevised
    How we know

    2672SetSamusJump:
    ⋮
    2681        LDA #$FC
    2682        STA ObjVertSpeed
    ⋮
    2686        LDA SamusGear
    ⋮
    2693LCFF3:  LDY #$18                ; gravity (high value -> low jump)
    2694        LDA SamusGear
    2695        AND #gr_HIGHJUMP
    2696        BEQ +                   ; branch if Samus doesn't have High Jump
    2697        LDY #$12                ; lower gravity value -> high jump!
    2698*       STY SamusGravity
    

    3328        ; High jump parameters
    3329        ld a, samus_jumpArrayBaseOffset - $1F ;$21
    ⋮
    3337            ; Normal jump parameters
    3338            ld a, samus_jumpArrayBaseOffset - $0F ;$31
    

    26def samus_jumpArrayBaseOffset = $40
    

    3884    ; Check if in linear portion of ascent
    3885    ld a, [samus_jumpArcCounter]
    3886    cp samus_jumpArrayBaseOffset
    3887    jr nc, .endIf_A
    

    3937    ; Increment jump counter
    3938    ld a, [samus_jumpArcCounter]
    3939    inc a
    3940    ld [samus_jumpArcCounter], a
    

    3892            ; Set speed, subtracting an extra 1 from it if we have high jump
    3893            ld a, [samusItems]
    3894            and itemMask_hiJump
    3895            srl a
    3896            ld b, a
    3897            ld a, -2 ; $FE
    3898            sub b
    

    5124  .InitialYSpeeds_Jumping:
    ⋮
    5130  .InitialYSpeeds_HiJumpJumping:
    

    4702Determine_Samus_YAcceleration:
    ⋮
    4719  .notSubmerged:
    

    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.

    In the claim ledger

13. ^The timer a hit sets starts at 50 in Metroid (SamusBlink, $32), 51 in Metroid II (samusInvulnerableTimer, $33), and 96 in Super Metroid (SamusInvincibilityTimer, $60).Codenmikstas/metroid-disassembly · alex-west/M2RoS · InsaneFirebat/sm_disassembly
    How we know

    2425    lda #$32            ;
    2426    sta SamusBlink          ;Samus has been hit. Set blink for 32 frames.
    

    7810    ; Give Samus i-frames
    7811    ld a, $33
    7812    ld [samusInvulnerableTimer], a
    

    LDA.W #$0060 STA.W SamusInvincibilityTimer

    Checked against the evidence by its author, an AI model, 2026-10-21.

    Checked by a second AI model, 2026-10-21.

    In the claim ledger