Mega Man 2/ROM map

The following article is a ROM map for Mega Man 2.

Gameplay Data

Mega Man

• 0x03891F = Mega Man's standstill x-velocity integer (Default: 00)
• 0x038920 = Mega Man's inching x-velocity integer (Default: 00)
• 0x038921 = Mega Man's walking x-velocity integer (Default: 01)
• 0x038922 = Mega Man's jumping x-velocity integer (Default: 01)
• 0x038923 = Mega Man's slip x-velocity integer (Default: 00)
• 0x038924 = Mega Man's landing upper x-velocity integer (Default: 00)
• 0x03892A = Mega Man's standstill x-velocity fraction (Default: 00)
• 0x03892B = Mega Man's inching x-velocity fraction (Default: 20)
• 0x03892C = Mega Man's walking x-velocity fraction (Default: 60)
• 0x03892D = Mega Man's jumping x-velocity fraction (Default: 50)
• 0x03892E = Mega Man's slip x-velocity fraction (Default: 80)
• 0x03892F = Mega Man's landing x-velocity fraction (Default: 00)
• 0x038A81 = Mega Man's jump height (Default: 80)

HP & Weapons Display

• 0x02C142 = How fast the robot masters' health fills up (Default: 03)
• 0x02E12B = How fast the fortress bosses' health fills up (Default: 03)
• 0x0352B2 = How fast Mega Man's health fills up while paused (Default: 03)
• 0x038315 = Maximum Energy for Mega Man (Default: 1C)
• 0x03831B = How fast Mega Man's health fills up in-game (Default: 07)
• 0x03835A = How fast Mega Man's weapon energy fills up in-game (Default: 07)
• 0x03CF79 = X position for energy bar (Default: 18)
• 0x03CF8F = X position for weapon bar (Default: 10)
• 0x03CFB1 = X position for boss bar (Default: 28)
• 0x03CFD8 = Graphics for Energy Bar (Default: 87) [NOTE: This define the leftmost tile (full HP graphic) and automatically picks to the right of it the remaining 4 tiles in descending order of HP, ex. 87>8B, DB>DF.]
• 0x03CFF5 = Y position for 1/7 energy (Default: 18)
• 0x03CFF6 = Y position for 2/7 energy (Default: 20)
• 0x03CFF7 = Y position for 3/7 energy (Default: 28)
• 0x03CFF8 = Y position for 4/7 energy (Default: 30)
• 0x03CFF9 = Y position for 5/7 energy (Default: 38)
• 0x03CFFA = Y position for 6/7 energy (Default: 40)
• 0x03CFFB = Y position for 7/7 energy (Default: 48)

Sound Effects during Stage

• 0x03524E = Changing selections in menu, Mega Man forming (Default: 2F)
• 0x0381E0 - 0x0381ED = Music played for each level
• 0x038685 = Sound for Mega Man landing (Default: 29)
• 0x03C59F = Sound for entering menu screen during action (Default: 32)
• 0x03C802 = Sound effect for Mega Man beamed down (Default: 30)

Pause Menu

• 0x0352AC = The amount of energy that E-Tanks set (Default: 1C)
• 0x03539E = Sound effect for turning off menu during action (Default: 30)
• 0x0353E8 = Starting Y position of the weapon icon sprites (Default: 44)
• 0x035403 = X position of the weapon icon sprites (Default: 0C)
• 0x03542C = Y position of Mega Man's health bar (Default: 44)
• 0x03543D = Y position of the first set of weapon energy bars (Default: 54)
• 0x03549C = Y position of the second set of weapon energy bars (Default: 44)
• 0x03559E - 0x03562D = Pause menu tile layout

Arrow and NEXT Sprites

• 0x03563C - 0x03564F (0x14) = sprite data
• 0x03563C = Y position
• 0x03563D = PPU Tile
• 0x03563E = Palette, mirroring
• 0x03563F = X position

format repeats

Weapon Icon Sprites

• 0x035650 - 0x03565B (0xC) = sprite data
• 0x035650 = P / Mega Buster (Default: 1F)
• 0x035651 = H / Atomic Fire (Default: 9F)
• 0x035652 = A / Air Shooter (Default: 9B)
• 0x035653 = W / Leaf Shield (Default: 99)
• 0x035654 = B / Bubble Lead (Default: 9D)
• 0x035655 = Q / Quick Boomerang (Default: 9C)
• 0x035656 = F / Flash Stopper (Default: 9A)
• 0x035657 = M / Metal Blade (Default: 9E)
• 0x035658 = C / Crash Bomber (Default: 10)
• 0x035659 = 1 / Item 1 (Default: 15)
• 0x03565A = 2 / Item 2 (Default: 16)
• 0x03565B = 3 / Item 3 (Default: 17)

E-Tank Menu Sprite

• 0x03565C - 0x03565F (0x4) = sprite data
• 0x03565C = Y position
• 0x03565D = PPU Tile
• 0x03565E = Palette, mirroring
• 0x03565F = X position

Extra Life Menu Sprite

• 0x035660 - 0x03566F (0x10) = sprite data
• 0x035660 = Y position
• 0x035661 = PPU Tile
• 0x035662 = Palette, mirroring
• 0x035663 = X position

format repeats

Items

• 0x0380D5 = Beginning amount of Health (Default: 1C)
• 0x0382FD = Amount of HP large Energy returns (Default: 0A)
• 0x038301 = Amount of HP small Energy returns (Default: 02)
• 0x03806C = Amount of E-Tanks set after starting a new game (Default: 00)
• 0x038382 = Maximum amount of E-Tanks you can carry (Default: 04) [NOTE: Carrying anything higher than 4 E-Tanks will generate bad passwords.]
• 0x038390 = Maximum amount of lives you can carry (Default: 63) [NOTE: Due to how lives actually work, 00 is game over and 01 is actually 0 lives, so 63 would yield a 98 live limit instead of the usual 99.]
• 0x03C1CB = Amount of E-Tanks set after continuing from a game over (Default: 00)

Power Ups

• 0x03C289 = Power Up from Heat Man (Default: 01)
• 0x03C28A = Power Up from Air Man (Default: 02)
• 0x03C28B = Power Up from Wood Man (Default: 04)
• 0x03C28C = Power Up from Bubble Man (Default: 08)
• 0x03C28D = Power Up from Quick Man (Default: 10)
• 0x03C28E = Power Up from Flash Man (Default: 20)
• 0x03C28F = Power Up from Metal Man (Default: 40)
• 0x03C290 = Power Up from Crash Man (Default: 80)
• 0x03C291 = Item # from Heat Man (Default: 01)
• 0x03C292 = Item # from Air Man (Default: 02)
• 0x03C293 = Item # from Wood Man (Default: 00)
• 0x03C294 = Item # from Bubble Man (Default: 00)
• 0x03C295 = Item # from Quick Man (Default: 00)
• 0x03C296 = Item # from Flash Man (Default: 04)
• 0x03C297 = Item # from Metal Man (Default: 00)
• 0x03C298 = Item # from Crash Man (Default: 00)

Screen Data

Stage Select

• 0x02EE10 - 0x02F1CF = Stage select screen layout
• 0x0340D8 = Routine for checking if a level has been cleared
• 0x0340E3 = First level of Wily's castle (Default: 08)
• 0x0340EC - 0x0340EF = Routine for checking if a level has been cleared
• 0x0340F6 = Confirming selection
• 0x034186 = First override palette for Boss posing screen (Default: 2C)
• 0x03418B = Second override palette for Boss posing screen (Default: 11)
• 0x0341BA = Preview boss music (Default: 0A)
• 0x0342ED = Selection for Bubble Man cursor
• 0x0344A9 - 0x0344B8 = Palette background for Stage Select Screen
• 0x0344B9 - 0x0344C8 = Palette foreground for Stage Select Screen
• 0x034551 = Beginning of Sprites for Stage Select Screen
• 0x03462E = Cursor position for Bubble Man Y position
• 0x034637 = Cursor position for Bubble Man X position
• 0x03464F - 0x034650 = Palette data for Boss posing screen
• 0x034651 - 0x03466E = Lines for Boss posing screen data (reverse order)
• 0x034670 = Pointer for Bubble Man Stage from selection
• 0x034671 = Pointer for Air Man Stage from selection
• 0x034672 = Pointer for Quick Man Stage from selection
• 0x034673 = Pointer for Wood Man Stage from selection
• 0x034674 = Pointer for Crash Man Stage from selection
• 0x034675 = Pointer for Flash Man Stage from selection
• 0x034676 = Pointer for Metal Man Stage from selection
• 0x034677 = Pointer for Heat Man Stage from selection
• 0x035994 = Path velocity in Wily's castle map (Default: 03)
• 0x038076 - 0x03807D = routine to see all weapons gained to go to Wily when selecting Start
• 0x03C264 - 0x03C269 = routine to see all weapons gained to go to Wily after gaining a weapon

Weapon Gained Screens

• 0x037D4A = How fast every letter gets revealed (Default: 07)

Mega Man

• 0x0249FE - 0x024A8A (0x8D) = Sprite data
• 0x0249FF = Y position
• 0x024A00 = PPU Tile
• 0x024A01 = Palette, mirroring
• 0x024A02 = X position

format repeats

Dr. Light

• 0x024A8B - 0x024AD7 (0x4D) = Sprite data
• 0x024A8C = Y position
• 0x024A8D = PPU Tile
• 0x024A8E = Palette, mirroring
• 0x024A8F = X position

format repeats

Title

• 0x036235 = Sound effect for switching between Normal and Difficult on Title (Default: 2F)
• 0x0362D1 = Difficulty select arrow sprite tile (Default: A2)
• 0x0362D2 = Palette, mirroring for arrow sprite (Default: 01)
• 0x0362D4 = X position for arrow (Default: 30)
• 0x0362D4 = Y position for arrow when selecting Normal (Default: 98)
• 0x0362D5 = Y position for arrow when selecting Difficult (Default: A8)
• 0x036322 = Removes all power ups and $00FD
• 0x03686D = Sprite 1 for Title
• 0x036877 = Sprite 2 for Title
• 0x036AAF - 0x036ABE = Palette for sprites on Title
• 0x036ACF - 0x036ADE = Palette background for Title
• 0x037341 = Title Screen Last byte (reversed order)
• 0x037700 = Title Screen First byte (reversed order)

Password Stuff

• 0x03700B = Password Y position (A,1) (Default: 40)
• 0x03700C = Password Y position (A,2) (Default: 40)
• 0x03700D = Password Y position (A,3) (Default: 40)
• 0x03700E = Password Y position (A,4) (Default: 40)
• 0x03700F = Password Y position (A,5) (Default: 40)
• 0x037010 = Password Y position (B,1) (Default: 50)
• 0x037011 = Password Y position (B,2) (Default: 50)
• 0x037012 = Password Y position (B,3) (Default: 50)
• 0x037013 = Password Y position (B,4) (Default: 50)
• 0x037014 = Password Y position (B,5) (Default: 50)
• 0x037015 = Password Y position (C,1) (Default: 60)
• 0x037016 = Password Y position (C,2) (Default: 60)
• 0x037017 = Password Y position (C,3) (Default: 60)
• 0x037018 = Password Y position (C,4) (Default: 60)
• 0x037019 = Password Y position (C,5) (Default: 60)
• 0x03701A = Password Y position (D,1) (Default: 70)
• 0x03701B = Password Y position (D,2) (Default: 70)
• 0x03701C = Password Y position (D,3) (Default: 70)
• 0x03701D = Password Y position (D,4) (Default: 70)
• 0x03701E = Password Y position (D,5) (Default: 70)
• 0x03701F = Password Y position (E,1) (Default: 80)
• 0x037020 = Password Y position (E,2) (Default: 80)
• 0x037021 = Password Y position (E,3) (Default: 80)
• 0x037022 = Password Y position (E,4) (Default: 80)
• 0x037023 = Password Y position (E,5) (Default: 80)
• 0x037024 = Password X position (A,1) (Default: 41)
• 0x037025 = Password X position (A,2) (Default: 51)
• 0x037026 = Password X position (A,3) (Default: 61)
• 0x037027 = Password X position (A,4) (Default: 71)
• 0x037028 = Password X position (A,5) (Default: 81)
• 0x037029 = Password X position (B,1) (Default: 41)
• 0x03702A = Password X position (B,2) (Default: 51)
• 0x03702B = Password X position (B,3) (Default: 61)
• 0x03702C = Password X position (B,4) (Default: 71)
• 0x03702D = Password X position (B,5) (Default: 81)
• 0x03702E = Password X position (C,1) (Default: 41)
• 0x03702F = Password X position (C,2) (Default: 51)
• 0x037030 = Password X position (C,3) (Default: 61)
• 0x037031 = Password X position (C,4) (Default: 71)
• 0x037032 = Password X position (C,5) (Default: 81)
• 0x037033 = Password X position (D,1) (Default: 41)
• 0x037034 = Password X position (D,2) (Default: 51)
• 0x037035 = Password X position (D,3) (Default: 61)
• 0x037036 = Password X position (D,4) (Default: 71)
• 0x037037 = Password X position (D,5) (Default: 81)
• 0x037038 = Password X position (E,1) (Default: 41)
• 0x037039 = Password X position (E,2) (Default: 51)
• 0x03703A = Password X position (E,3) (Default: 61)
• 0x03703B = Password X position (E,4) (Default: 71)
• 0x03703C = Password X position (E,5) (Default: 81)
• 0x037056 = Password related (A,1)
• 0x03709B = Password related (E,5)

Weapon Attributes

Mega Buster

• 0x03DA7C - 0x03DA8F (0x14) = Routine

$DA6C:A5 27     LDA $0027 ;Load single frame input poll
$DA6E:29 02     AND #$02 ;Check bit 2 (Whether player pressed B)
$DA70:F0 2B     BEQ $DA9C ;If bit 2 not on, player didn't press B, skip to end and leave subroutine
$DA72:A2 04     LDX #$04 ;Loads X with #$04
$DA74:BD 20 04  LDA $0420,X ;Check memory position $0424, status of third projectile slot
$DA77:10 07     BPL $DA80 ;Branch if Bit 7 is not set - Bit 7 of 424 is 1 if a projectile exists and 0 if not. In other words, if a projectile is in this slot, continue, otherwise jump to shooting routine
$DA79:CA        DEX ;Decrement X
$DA7A:E0 01     CPX #$01 ;Check if X is 1
$DA7C:D0 F6     BNE $DA74 ;If X isn't, branch back to projectile check. This repeats until you have checked all 3 projectile slots
$DA7E:F0 1D     BEQ $DA9C ;If it is 1, you've checked every projectile slot, end subroutine
$DA80:A9 24     LDA #$24 ;Load Accumulator w/ #$24 
$DA82:20 51 C0  JSR $C051 ;Jump to sound effect routine (Play sound #24, Mega Buster shot)
$DA85:A0 00     LDY #$00 ;Load Y with #$00
$DA87:20 E0 D3  JSR $D3E0 ;Jump to bullet generation routine - X, set by the previous loop, is the projectile slot to create bullet in. Y is bullet type, in this case 0 is Mega Buster shots
$DA8A:A9 0F     LDA #$0F ;Load Accumulator with #$0F
$DA8C:85 36     STA $0036 ;Set timer for how long it takes MM to lower arm after firing to 15 frames
$DA8E:A9 01     LDA #$01 ;Load Accumulator with #$01
$DA90:85 3D     STA $003D ;Set sprite for firing this to 1, buster shot (0 is none, 2 is super arm, 3 is throw) 
$DA92:A6 2C     LDX $002C ;Load $002C, Mega Man's current state, into X
$DA94:18        CLC ;Always clear carry flag before addition!
$DA95:7D D4 D3  ADC $D3D4,X ;Add something at $D3D4 + $002C's position. I think this is deciding which shooting sprite to use (2C indicates whether MM is standing, jumping, walking, etc). 
$DA98:8D 00 04  STA $0400 ;Store Rockman animation
$DA9B:18        CLC ;Clear carry
$DA9C:60        RTS ;We're done here folks

• 0x03D4A7 = Velocity of Mega Man's buster shots (Default: 04) [NOTE: Shots that are too fast will not be able to properly register hits at all, so avoid going beyond around 0B.]
• 0x03DA83 = Maximum number of buster shots on-screen (Default: 04) [NOTE: Values 00, 01, and 10 and beyond are all invalid, while 02 is actually 1, so 04 would actually mean 3 shots on-screen.]
  • What this literally is is how far into the object handling chart in memory ($0420 - $043F) the projectile generation loop is going. Weapons are normally stored in $0422 - $0429, so with a maximum of 3 bullets on screen, the loop checks $0424, $0423, and $0422. Increasing this past 0F enters the enemy handling range ($0430~$043F)
• 0x03DA91 = Sound effect for basic Mega Man shooting (Default: 24)

Atomic Fire

• 0x03DD61 = Charge time between first and second level (Default: 7D)
• 0x03DD67 = Charge time between first and third level (Default: BB) [NOTE: If this value is lower than the value above, then that value is overwritten and it jumps straight to the third charge level.]
• 0x03DE46 - 0x03DE48 = Sound effect for Atomic Heat charge per level (Default: 35, 36, 37)
• 0x03DE49 - 0x03DE50 = First and third color of Atomic Heat per level, including non-charging (Default: 0F15, 3115, 352C, 3030)
• 0x03DE55 - 0x03DE57 = Amount of energy that Atomic Heat uses per shot per level (Default: 01, 06, 0A)

Air Shooter

• 0x03DAC3 - 0x03DAF5 (0x33) = Routine

$DAB3:A5 27     LDA $0027 = #$00
$DAB5:29 02     AND #$02
$DAB7:F0 2B     BEQ $DAE4
$DAB9:A2 04     LDX #$04
$DABB:BD 20 04  LDA $0420,X @ $0480 = #$40
$DABE:30 24     BMI $DAE4
$DAC0:CA        DEX
$DAC1:E0 01     CPX #$01
$DAC3:D0 F6     BNE $DABB
$DAC5:A2 04     LDX #$04
$DAC7:86 01     STX $0001 = #$74
$DAC9:A0 02     LDY #$02
$DACB:20 E0 D3  JSR $D3E0
$DACE:A6 01     LDX $0001 = #$74
$DAD0:CA        DEX
$DAD1:E0 01     CPX #$01
$DAD3:D0 F2     BNE $DAC7
$DAD5:A9 3F     LDA #$3F
$DAD7:20 51 C0  JSR $C051
$DADA:38        SEC
$DADB:A5 9D     LDA $009D = #$16
$DADD:E9 02     SBC #$02
$DADF:85 9D     STA $009D = #$16
$DAE1:4C 8A DA  JMP $DA8A
$DAE4:38        SEC
$DAE5:60        RTS

• 0x03DAE6 = Sound effect for Air Shooter (Default: 3F)
• 0x03DAEE = Amount of energy that Air Shooter uses per shot (Default: 02)

Leaf Shield

• 0x03DF0D = Sound effect for Leaf Shield turning (Default: 01)
• 0x03DF1F = Sound effect for Leaf Shield appearing (Default: 31)
• 0x03DF72 = Amount of energy that Leaf Shield uses per shot (Default: 03)

Bubble Lead

• 0x03DB34 = Sound effect for Bubble Lead (Default: 24)
• 0x03DB3D = Amount of Bubble Lead shots before reducing energy (Default: 02)

Quick Boomerang

• 0x03DB4B - 0x03DB89 (0x3F) = Routine

$DB3B:A5 27     LDA $0027 = #$00
$DB3D:29 02     AND #$02
$DB3F:D0 0A     BNE $DB4B
$DB41:A5 AB     LDA $00AB = #$03
$DB43:C9 0B     CMP #$0B
$DB45:F0 04     BEQ $DB4B
$DB47:E6 AB     INC $00AB = #$03
$DB49:18        CLC
$DB4A:60        RTS
$DB4B:A2 05     LDX #$05
$DB4D:BD 20 04  LDA $0420,X @ $0425 = #$C3
$DB50:10 07     BPL $DB59
$DB52:CA        DEX
$DB53:E0 01     CPX #$01
$DB55:D0 F6     BNE $DB4D
$DB57:F0 1F     BEQ $DB78
$DB59:A0 05     LDY #$05
$DB5B:20 E0 D3  JSR $D3E0
$DB5E:A9 24     LDA #$24
$DB60:20 51 C0  JSR $C051
$DB63:E6 AC     INC $00AC = #$04
$DB65:A5 AC     LDA $00AC = #$04
$DB67:C9 08     CMP #$08
$DB69:D0 06     BNE $DB71
$DB6B:A9 00     LDA #$00
$DB6D:85 AC     STA $00AC = #$04
$DB6F:C6 A0     DEC $00A0 = #$09
$DB71:A9 00     LDA #$00
$DB73:85 AB     STA $00AB = #$03
$DB75:4C 8A DA  JMP $DA8A
$DB78:38        SEC
$DB79:60        RTS

• 0x03DB54 = Fire rate velocity for Quick Boomerang (Default: 0B)
• 0x03DB6F = Sound effect for Quick Boomerang (Default: 24)
• 0x03DB78 = Amount of Quick Boomerang shots before reducing energy (Default: 08)

Quick Boomerang Mechanics

• 0x03DFDE - 0x03E025 (0x48) = Routine

$DFCE:BD E0 04  LDA $04E0,X @ $04E3 = #$0D
$DFD1:C9 12     CMP #$12
$DFD3:B0 14     BCS $DFE9
$DFD5:38        SEC
$DFD6:BD 60 06  LDA $0660,X @ $0663 = #$DB
$DFD9:E9 4B     SBC #$4B
$DFDB:9D 60 06  STA $0660,X @ $0663 = #$DB
$DFDE:BD 40 06  LDA $0640,X @ $0643 = #$FE
$DFE1:E9 00     SBC #$00
$DFE3:9D 40 06  STA $0640,X @ $0643 = #$FE
$DFE6:4C 0F E0  JMP $E00F
$DFE9:D0 08     BNE $DFF3
$DFEB:BD 20 04  LDA $0420,X @ $0423 = #$C3
$DFEE:49 40     EOR #$40
$DFF0:9D 20 04  STA $0420,X @ $0423 = #$C3
$DFF3:BD E0 04  LDA $04E0,X @ $04E3 = #$0D
$DFF6:C9 23     CMP #$23
$DFF8:D0 04     BNE $DFFE
$DFFA:5E 20 04  LSR $0420,X @ $0423 = #$C3
$DFFD:60        RTS
$DFFE:18        CLC
$DFFF:BD 60 06  LDA $0660,X @ $0663 = #$DB
$E002:69 4B     ADC #$4B
$E004:9D 60 06  STA $0660,X @ $0663 = #$DB
$E007:BD 40 06  LDA $0640,X @ $0643 = #$FE
$E00A:69 00     ADC #$00
$E00C:9D 40 06  STA $0640,X @ $0643 = #$FE
$E00F:FE E0 04  INC $04E0,X @ $04E3 = #$0D
$E012:20 EF EE  JSR $EEEF
$E015:60        RTS

• 0x03DFE2 = How far Quick Boomerang flies out (Default: 12)
• 0x03DFFF = How far Quick Boomerang flies down before coming up (Default: 40)
• 0x03E007 = How far Quick Boomerang flies back (Default: 23)

Flash Stopper

• 0x03DC41 - 0x03DC5C (0x1C) = Routine

$DC31:A5 27     LDA $0027 = #$00
$DC33:29 02     AND #$02
$DC35:F0 1F     BEQ $DC56
$DC37:A2 02     LDX #$02
$DC39:AD 22 04  LDA $0422 = #$00
$DC3C:30 18     BMI $DC56
$DC3E:A0 08     LDY #$08
$DC40:20 E0 D3  JSR $D3E0
$DC43:A9 01     LDA #$01
$DC45:8D A6 05  STA $05A6 = #$01
$DC48:A9 21     LDA #$21
$DC4A:20 51 C0  JSR $C051

• 0x03DC59 = Sound effect for Flash Stopper (Default: 21)

Flash Stopper Mechanics

• 0x03E168 - 0x03E19F (0x38) = Routine

$E158:DE 20 06  DEC $0620,X @ $0680 = #$03
$E15B:D0 15     BNE $E172
$E15D:A9 0F     LDA #$0F
$E15F:9D 20 06  STA $0620,X @ $0680 = #$03
$E162:C6 A1     DEC $00A1 = #$1C
$E164:D0 0C     BNE $E172
$E166:5E 20 04  LSR $0420,X @ $0480 = #$00
$E169:A9 00     LDA #$00
$E16B:85 AA     STA $00AA = #$00
$E16D:A9 01     LDA #$01
$E16F:85 50     STA $0050 = #$00
$E171:60        RTS
$E172:A9 01     LDA #$01
$E174:85 AA     STA $00AA = #$00
$E176:A9 00     LDA #$00
$E178:85 50     STA $0050 = #$00
$E17A:85 4F     STA $004F = #$00
$E17C:A9 80     LDA #$80
$E17E:9D A0 04  STA $04A0,X @ $0500 = #$A6
$E181:18        CLC
$E182:65 1F     ADC $001F = #$00
$E184:9D 60 04  STA $0460,X @ $04C0 = #$00
$E187:AD 40 04  LDA $0440 = #$00
$E18A:69 00     ADC #$00
$E18C:9D 40 04  STA $0440,X @ $04A0 = #$B4
$E18F:60        RTS

• 0x03D49D = Duration until weapon energy starts to drain (Default: 0F)

Metal Blade

• 0x03DC5D - 0x03DC65 (0x9) = Routine

$DC4D:A9 0F     LDA #$0F
$DC4F:85 36     STA $0036 = #$00
$DC51:A9 03     LDA #$03
$DC53:4C 90 DA  JMP $DA90
$DC56:38        SEC
$DC57:60        RTS

• 0x03DBC9 = Sound effect for Metal Blade (Default: 23)
• 0x03DBD2 = Amount of Metal Blade shots before reducing energy (Default: 04)

Crash Bomber

• 0x03DBA6 = Sound effect for Crash Bomber (Default: 24)
• 0x03DB99 = Amount of energy that Crash Bomber uses per shot (Default: 04)
• 0x03E089 = Sound effect for Crash Bomber clasping wall (Default: 2E)
• 0x03E09C = Timer until Crash Bomber detonates (Default: 7E)
• 0x03E0DA = Sound effect for Crash Bomber exploding (Default: 2B)

Items

• 0x03DC85 = Amount of energy that Item 1 uses per use (Default: 02)
• 0x03E230 = Amount of time before subtracting one energy from Item 2 (Default: 13)
• 0x03E34C = Amount of time before subtracting one energy from Item 3 (Default: 1F)

Enemy Behavior

Attack Power Table

• 0x02E9C4 = Wood Man's contact damage (Default: 08)
• 0x02E9C8 = Flash Man's contact damage (Default: 06)
• 0x03ED76 = Crabbot's contact damage (Default: 04)
• 0x03ED78 = Grand Croaker's contact damage (Default: 04)
• 0x03ED79 = Petit Croaker's contact damage (Default: 01)
• 0x03ED82 = Bubble Bat's contact damage (Default: 04)
• 0x03ED83 = Robo-Rabbit's contact damage (Default: 04)
• 0x03ED84 = Robo-Rabbit's projectile carrot (Default: 02)
• 0x03ED85 = Hot Dog's contact damage (Default: 08)
• 0x03ED87 = Hot Dog's projectile fire stream (Default: 04)
• 0x03ED89 = Mecha Monkey's contact damage (Default: 04)
• 0x03ED8B = Atomic Chicken's contact damage (Default: 04)
• 0x03EDA1 = Returning Sniper Joe's projectile pellet (Default: 02)
• 0x03EDA4 = Pipi's contact damage (Default: 04)
• 0x03EDA6 = Pipi's egg projectile (Default: 04)
• 0x03EDA8 = Copipi's contact damage (Default: 02)
• 0x03EDB7 = Crazy Cannon's contact damage (Default: 04)
• 0x03EDB9 = Crazy Cannon's projectile pellet (Default: 02)
• 0x03EDBA = Sniper Armor's contact damage (Default: 08)
• 0x03EDBB = Sniper Armor's projectile pellet (Default: 04)
• 0x03EDBC = Schworm's contact damage (Default: 02)
• 0x03EDBD = Schworm's projectile snake rod (Default: 02)
• 0x03EDCD = Wood Man's Leaf Shield (Default: 08)
• 0x03EDCE = Wood Man's Falling Leaves (Default: 04)

Heat Man

• 0x02C16E - 0x02C--- (0x??) = Routine for attack
• 0x02C207 = Atomic Fire 1's y-velocity (Default: 07)
• 0x02C208 = Atomic Fire 2's y-velocity (Default: 05)
• 0x02C209 = Atomic Fire 3's y-velocity (Default: 03)
• 0x02C20A = Atomic Fire 1's x-velocity (Default: 3A) [NOTE: Unlike other instances of velocity, lower values for these x-velocities means faster velocity.]
• 0x02C20B = Atomic Fire 2's x-velocity (Default: 2E)
• 0x02C20C = Atomic Fire 3's x-velocity (Default: 1C)
• 0x02C1BB = Projectile type (Default: 58)
• 0x02C1A1 = Number of Atomic Fires thrown (Default: 02) [NOTE: Extra shots tend to be glitchy.]
• 0x02C253 = Charge x-velocity (Default: 04)
• 0x02C29D = Delay 1 before charge (Default: 1F) [NOTE: After Heat Man is damaged, he will wait before charging. This and the two values below are randomly chosen as the delay interval.]
• 0x02C29E = Delay 2 before charge (Default: 3E)
• 0x02C29F = Delay 3 before charge (Default: 5D)

Flash Man

• 0x02C966 - 0x02CAF8 (0x193) = Routine for attack
• 0x02C97D = Walk x-velocity fraction (Default: 06)
• 0x02C982 = Walk x-velocity integer (Default: 01)
• 0x02C98B = Delay before Time Stopper (Default: BB) [NOTE: It only counts down while the boss is walking.]
• 0x02CA09 = Number of pellets to shoot (Default: 06)
• 0x02CA52 = Length of Time Stopper/projectile frequency? (Default: 06) [NOTE: Uncertain about value's function; alter it at own risk.]
• 0x02CA71 = Projectile type (Default: 35)
• 0x02CA81 = Pellet x-velocity (Default: 08)
• 0x02CAC6 = Jump x-velocity integer (Default: 00)
• 0x02CACE = Jump y-velocity integer (Default: 04)

Metal Man

• 0x02CBB5 = Jump height 1 (Default: 06) [NOTE: Anything higher than 07 will make Metal Man bonk the ceiling.]
• 0x02CBB6 = Jump height 2 (Default: 05)
• 0x02CBB7 = Jump height 3 (Default: 04)
• 0x02CC1D = Metal Blade frequency? (Default: 06) [NOTE: Uncertain about value's function, seems to change behavior if value's different than 06; alter it at own risk.]
• 0x02CC29 = Metal Blade sound (Default: 20)
• 0x02CC2D = Projectile type (Default: 5C)
• 0x02CC3F = Metal Blade x-velocity (Default: 04)

Crash Man

• 0x02CCF2 = Walk x-velocity fraction (Default: 47)
• 0x02CCF7 = Walk x-velocity integer (Default: 01)
• 0x02CD07 = Jump behavior (Default: 27) [NOTE: If changed to 0x17, he always jumps. If any value other than 0x27 or 0x17, he doesn't react to your attacks with a jump anymore.]
• 0x02CD2A = Jump y-velocity integer (Default: 06)
• 0x02CDAF = Jump y-velocity fraction (Default: 44)
• 0x02CDD3 = [NOTE: Unsure; changing this to another value makes it so Crash Man always shoots when jumping] (Default: 5E)
• 0x02CDEE = Crash Bomber x-velocity integer (Default: 06)

Quick Man

• 0x02C86E = Number of Quick Boomerangs (Default: 03)
• 0x02C872 = Projectile type (Default: 59)
• 0x02C882 = Quick Boomerang delay in frames before second motion (Default: 25)
• 0x02C887 = Boomerang x-velocity first motion (Default: 04)
• 0x03B726 = Boomerang x-velocity second motion (Default: 04)
• 0x02C8A3 = Medium jump y-velocity (Default: 07)
• 0x02C8A4 = High jump y-velocity (Default: 08)
• 0x02C8A5 = Low jump y-velocity (Default: 04)
• 0x02C8E4 = Running time in frames (Default: 3E)
• 0x02C8DF = Running velocity integer (Default: 02)

Bubble Man

• 0x02C70B = Landing speed integer (Default: FF)
• 0x02C6D3 = Rising speed integer (Default: 01)
• 0x02C74F = Gun projectile type (Default: 5A)

Wood Man

• 0x02C537 = Delay between rising leaves (Default: 12)
• 0x02C5DD = Jump y-velocity integer (Default: 04)
• 0x02C5E2 = Jump x-velocity integer (Default: 01)
• 0x02C5A9 = Leaf Shield launch x-velocity integer (Default: 04)
• 0x02C553 = Number of falling leaves (Default: 03)
• 0x02C576 = Falling leaf x-velocity integer (Default: 02)
• 0x02C567 = Falling leaf y-position start (Default: 20)
• 0x02C522 = Leaf Shield projectile type (Default: 61)
• 0x02C557 = Falling leaves projectile type (Default: 62)
• 0x02C542 = Rising leaves projectile type (Default: 62)
• 0x03DA34 = Leaf Shield fall y-velocity? (Default: 00) [NOTE: Uncertain about value's function; alter it at own risk.]
• 0x03D8F6 = [NOTE: Unsure; changing this value to 06 makes an interesting Leaf Shield pattern.] (Default: 02)
• 0x03B855 = Leaf fall y-velocity? (Default: 20) [NOTE: Uncertain about value's function; alter it at own risk. Unlike other instances of velocity, lower values means faster velocity. Values 40 and higher make it so that it doesn't fall. High numbers make leaves instantly despawn, causing faster patterns]

Air Man

• 0x02C2F3 - 0x02C50A (0x218) = Routine for attack
• 0x02C30C = Number of tornado patterns before jump phase (Default: 03)
• 0x02C393 - 0x02C428 (0x96) = Tornado properties [NOTE: Air Man has 5 possible tornado patterns, each with 6 tornadoes. In each 30-byte block of properties, the first 6 bytes correspond to the tornadoes in the first pattern, the next 6 bytes correspond to the tornadoes in the second pattern, etc.]
  • 0x02C393 - 0x02C3B0 (0x1E) = y-velocity fractions
  • 0x02C3B1 - 0x02C3CE (0x1E) = y-velocity integers
  • 0x02C3CF - 0x02C3EC (0x1E) = x-velocity fractions
  • 0x02C3ED - 0x02C40A (0x1E) = x-velocity integers
  • 0x02C40B - 0x02C428 (0x1E) = delay before tornado finishes deploying
• 0x02C4DD = First jump y-velocity fraction (Default: E6)
• 0x02C4DE = Second jump y-velocity fraction (Default: 76)
• 0x02C4E0 = First jump y-velocity integer (Default: 04)
• 0x02C4E1 = Second jump y-velocity integer (Default: 07)
• 0x02C4E3 = First jump x-velocity fraction (Default: 39)
• 0x02C4E4 = Second jump x-velocity fraction (Default: 9A)
• 0x02C4E6 = First jump x-velocity integer (Default: 01)
• 0x02C4E7 = Second jump x-velocity integer (Default: 01)

Wily Machine

• 0x02DA2E = Phase 1 weakness #1 to disable (Default: 02) [NOTE: Only one damage table is provided for Wily Machine's weaknesses. However, during each phase, the game manually ignores damage when you have certain weapons equipped. By default, damage is negated if you have Air Shooter or Quick Boomerang equipped in phase 1, or if you have Atomic Fire equipped in phase 2.]
• 0x02DA32 = Phase 1 weakness #2 to disable (Default: 05)
• 0x02DA3A = Phase 2 weakness to disable (Default: 01)

Boss Weakness Damage

(Credit to Overseer190 )

[NOTE: This is based on the USA version of Mega Man 2. Japanese values are located further up in the ROM. Also, any hex value from 00 to 79 (0 to 127) deals damage to the enemy, whereas hex values ranging from 80 to FF (128 to 255) will fully heal the enemy.]

Mega Buster

• 0x02E952 = Heat Man (Default: 02)
• 0x02E953 = Air Man (Default: 02)
• 0x02E954 = Wood Man (Default: 01)
• 0x02E955 = Bubble Man (Default: 01)
• 0x02E956 = Quick Man (Default: 02)
• 0x02E957 = Flash Man (Default: 02)
• 0x02E958 = Metal Man (Default: 01)
• 0x02E959 = Crash Man (Default: 01)
• 0x02E95A = Mecha Dragon (Default: 01)
• 0x02E95B = Picopico-kun (Default: 00)
• 0x02E95C = Guts Tank (Default: 01)
• 0x02E95D = Boobeam Trap (Default: 00)
• 0x02E95E = Wily Machine 2 (Default: 01)
• 0x02E95F = Alien (Default: FF)

Atomic Fire

[NOTE: An uncharged shot uses the Mega Buster's damage chart, a partially charged shot uses the Mega Buster's damage chart and multiplies the value by 2, always rounding up to the nearest whole number, and a charged shot uses the table below.]

• 0x02E960 = Heat Man (Default: FF)
• 0x02E961 = Air Man (Default: 06)
• 0x02E962 = Wood Man (Default: 0E)
• 0x02E963 = Bubble Man (Default: 00)
• 0x02E964 = Quick Man (Default: 0A)
• 0x02E965 = Flash Man (Default: 06)
• 0x02E966 = Metal Man (Default: 04)
• 0x02E967 = Crash Man (Default: 06)
• 0x02E968 = Mecha Dragon (Default: 08)
• 0x02E969 = Picopico-kun (Default: 00)
• 0x02E96A = Guts Tank (Default: 08)
• 0x02E96B = Boobeam Trap (Default: 00)
• 0x02E96C = Wily Machine 2 (Default: 0E)
• 0x02E96D = Alien (Default: FF)

Air Shooter

• 0x02E96E = Heat Man (Default: 02)
• 0x02E96F = Air Man (Default: 00)
• 0x02E970 = Wood Man (Default: 04)
• 0x02E971 = Bubble Man (Default: 00)
• 0x02E972 = Quick Man (Default: 02)
• 0x02E973 = Flash Man (Default: 00)
• 0x02E974 = Metal Man (Default: 00)
• 0x02E975 = Crash Man (Default: 0A)
• 0x02E976 = Mecha Dragon (Default: 00)
• 0x02E977 = Picopico-kun (Default: 00)
• 0x02E978 = Guts Tank (Default: 00)
• 0x02E979 = Boobeam Trap (Default: 00)
• 0x02E97A = Wily Machine 2 (Default: 01)
• 0x02E97B = Alien (Default: FF)

Leaf Shield

• 0x02E97C = Heat Man (Default: 00)
• 0x02E97D = Air Man (Default: 08)
• 0x02E97E = Wood Man (Default: FF)
• 0x02E97F = Bubble Man (Default: 00)
• 0x02E980 = Quick Man (Default: 00)
• 0x02E981 = Flash Man (Default: 00)
• 0x02E982 = Metal Man (Default: 00)
• 0x02E983 = Crash Man (Default: 00)
• 0x02E984 = Mecha Dragon (Default: 00)
• 0x02E985 = Picopico-kun (Default: 00)
• 0x02E986 = Guts Tank (Default: 00)
• 0x02E987 = Boobeam Trap (Default: 00)
• 0x02E988 = Wily Machine 2 (Default: 00)
• 0x02E989 = Alien (Default: FF)

Bubble Lead

• 0x02E98A = Heat Man (Default: 06)
• 0x02E98B = Air Man (Default: 00)
• 0x02E98C = Wood Man (Default: 00)
• 0x02E98D = Bubble Man (Default: FF)
• 0x02E98E = Quick Man (Default: 00)
• 0x02E98F = Flash Man (Default: 02)
• 0x02E990 = Metal Man (Default: 00)
• 0x02E991 = Crash Man (Default: 01)
• 0x02E992 = Mecha Dragon (Default: 00)
• 0x02E993 = Picopico-kun (Default: 00)
• 0x02E994 = Guts Tank (Default: 01)
• 0x02E995 = Boobeam Trap (Default: 00)
• 0x02E996 = Wily Machine 2 (Default: 00)
• 0x02E997 = Alien (Default: 01)

Quick Boomerang

• 0x02E998 = Heat Man (Default: 02)
• 0x02E999 = Air Man (Default: 02)
• 0x02E99A = Wood Man (Default: 00)
• 0x02E99B = Bubble Man (Default: 02)
• 0x02E99C = Quick Man (Default: 00)
• 0x02E99D = Flash Man (Default: 00)
• 0x02E99E = Metal Man (Default: 04)
• 0x02E99F = Crash Man (Default: 01)
• 0x02E9A0 = Mecha Dragon (Default: 01)
• 0x02E9A1 = Picopico-kun (Default: 00)
• 0x02E9A2 = Guts Tank (Default: 02)
• 0x02E9A3 = Boobeam Trap (Default: 00)
• 0x02E9A4 = Wily Machine 2 (Default: 01)
• 0x02E9A5 = Alien (Default: FF)

Crash Bombs

• 0x02E9A6 = Heat Man (Default: FF)
• 0x02E9A7 = Air Man (Default: 00)
• 0x02E9A8 = Wood Man (Default: 02)
• 0x02E9A9 = Bubble Man (Default: 02)
• 0x02E9AA = Quick Man (Default: 04)
• 0x02E9AB = Flash Man (Default: 03)
• 0x02E9AC = Metal Man (Default: 00)
• 0x02E9AD = Crash Man (Default: 00)
• 0x02E9AE = Mecha Dragon (Default: 01)
• 0x02E9AF = Picopico-kun (Default: 00)
• 0x02E9B0 = Guts Tank (Default: 01)
• 0x02E9B1 = Boobeam Trap (Default: 00) [NOTE: This value is unused as Boobeam Traps take 4 damage from being hit by "a weapon that does not have a 'no hit' flag." The location of this flag is unknown.]
• 0x02E9B2 = Wily Machine 2 (Default: 04)
• 0x02E9B3 = Alien (Default: FF)

Metal Blade

• 0x02E9B4 = Heat Man (Default: 01)
• 0x02E9B5 = Air Man (Default: 00)
• 0x02E9B6 = Wood Man (Default: 02)
• 0x02E9B7 = Bubble Man (Default: 04)
• 0x02E9B8 = Quick Man (Default: 00)
• 0x02E9B9 = Flash Man (Default: 04)
• 0x02E9BA = Metal Man (Default: 0E)
• 0x02E9BB = Crash Man (Default: 00)
• 0x02E9BC = Mecha Dragon (Default: 00)
• 0x02E9BD = Picopico-kun (Default: 00)
• 0x02E9BE = Guts Tank (Default: 00)
• 0x02E9BF = Boobeam Trap (Default: 00)
• 0x02E9C0 = Wily Machine 2 (Default: 01)
• 0x02E9C1 = Alien (Default: FF)