Mega Man IV is the fourth entry in the Game Boy Mega Man series. It's actually really good. It was also the last one to feature robot masters from the NES games.

Debug Content

Debug Menu

Use the Game Shark code 011A0ADF or Game Genie code 1A9-BAF-A2A and select "Game Start". This should bring up the "Thank You For Playing" screen similar to that seen at the end of the game but without Mega Man sprite. Need to mention, this screen not using the same screen resources as the end of the game, but completely different copy of the same data.

From here, hit A or B to access the debug menu.

If Game Shark code used, be sure to disable it once you've entered the menu.

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  TOAD-TOMS: Marks the appropriate boss as defeated and give you their weapon. Self-explanatory except for TOMS, which is Charge Man.


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  BLDA: Marks the Wily Tank stage as completed.


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  BKBA: Marks Ballade as defeated and gives you the Ballade Cracker weapon.


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  BEAT, WILY: Gives you the appropriate letter(s).


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  ME: Number of mini E-tanks. Every fourth mini tank gives you a full E-Tank.


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  WP: Number of Weapon Tanks (Max 4)


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  SP: Super Tank toggle.


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  EB: Energy Balancer toggle.


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  PC: Number of P-Chips. This value goes in fours, so the maximum value is 996.


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  ZA: Number of lives.


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  BKI: All weapons toggle. NL is OFF, and FL is ON. Note that this does not mark all of the bosses as defeated.


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  HERAZ: Unlimited Tanks toggle.


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  MUTEKIM: Invincibility variable. 00 turns this off. 01 will give you infinite energy, but you can still get hit, fall down pits, and get killed by spikes. 02 will give you infinite energy, disable all damage, and disable spikes. It will also turn all pits into bouncy surfaces! Just hold the A button to jump out.


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  CNTNUPT: Checkpoint variable. 00 is the start of the level, 01 is the midpoint, and 02 is the last checkpoint.


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  STAGED: Stage warp. Press Start to warp to the level of your choice. Note that you MUST warp to a level to keep any changes made with the debug menu.
  
  
  
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    01: Toad Man.
  
  
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    02: Bright Man.
  
  
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    03: Pharaoh Man.
  
  
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    04: Ring Man.
  
  
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    05: Crystal Man.
  
  
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    06: Napalm Man.
  
  
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    07: Stone Man.
  
  
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    08: Charge Man.
  
  
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    09: Wily Tank.
  
  
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    0A: Ballade.
  
  
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    0B: Ballade—Entrance.
  
  
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    0C: Wily Spaceship—Interior.
  
  
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    0D: Wily Spaceship—Teleport System.
  
  
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    0E: Wily Capsule Fight.
  
  
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    0F: Got Weapon screen.
  
  
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    10: Dr. Light opening scene.
  
  
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    11: Wily Tank destruction.
  
  
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    12: Guard Satellite.
  
  
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    13: Wily Spaceship—Exterior.
  
  
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    14: Wily Machine #4 cutscene.
  
  
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    15: Wily Machine #4.
  
  
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    16: Escape from Wily Spaceship.
  
  
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    17: Wily Spaceship destruction.
  
  
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    18: Robot Master demos.
  
  
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    19: Thank You For Playing screen.
  
  
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    1A: Debug intro.
  
  
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    1B: Wily Spaceship—Before Wily Machine #4.
  
  
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    1C: Wily Tank attack.
  
  
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    1D: Wily Saucer cutscene.
  
  
  
  


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  RECORD: Records a demo that can be played back later.

Select any stage from 01 to 09. Then, set record on REC, and press Start. You should go to the boss recording room. If you die, beat the Robot Master, or press Start, the demo will stop recording. PLY will play back the demo of that level, if you've recorded one. HON will play the Robot Master demos seen at the end of the game.

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  SNDNO: Sound test.


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  EXIT: Exits the debug menu. This will discard any changes.

Miscellaneous Debug Text

The following text were used for debugging purposes, and even assigned to some debug routines which intended to be activated with some buttons, but all routines are unreferenced at all in the release versions. Text resources starts at 0x5032E in the ROM.

INITIALIZED

BALLADE A MINI

BALLADE A MAX

KOUHAN MINI

KOUHAN MAX

BLDB MIN

BLDB MAX

Dr. Light Picture

Icons of Dr. Light talking and blinking are found with the rest of the Light Lab graphics. These should be used when he talks to Mega Man, but they aren't. They were probably cut to free up space in the dialogue box.

Early Screens

Stage Select

More traditional stage select menu graphics exist in the ROM. These were replaced with the much cooler looking stage select seen in the final game. Mega Man III had a nearly identical selection layout.

The tilemap for this early stage select is still in the game at 0x3F69C.

The BEAT and WILY letters would appear over the stage icons after they were collected. Both of the Dr. Wily icons are taken directly from Mega Man III.

Password

Early	Final

A tilemap for an early password screen starts at 0x3F93C in the game ROM. This password screen is similar to the ones seen in Mega Man 3 and Mega Man 5, with a 6x6 grid and two different markers.

The final password screen uses a 6x4 grid, but uses three different (and easier to denote) grid markers, very much like the password system used in the original Game Boy version of Bionic Commando, released the previous year.

Street Fighter II

For some reason, a mockup screen for a portable Street Fighter II is in the game ROM! The tilemap for this screen starts at 0x781A4 in the game, and the tileset starts at 0x7830C. It seems this were another part of the debug screen mentioned above, it uses the same resources format and may be displayed with the same routine as the debug's screen intro picture, but were removed from the main pointer table. Use Game Genie codes in addition to debug activation code to see this screen instead of "THANK YOU FOR PLAYING" picture 969-F8A-D5A + 419-F9A-A27.

An actual Game Boy Street Fighter II came out in 1995, about two years after this game was released. However, that game wasn't developed by Minakuchi Engineering, who worked on this game. Based on a code comparison, that port was done by Sun L.

Unused Music

Four tracks are unused in the final game. These are all alternate versions of existing tracks.

Beat

A different version of the Beat acquisition music. It's pretty close to the final version.

Fortress Attack

An early version of the music used for the Wily Fortress attack cutscene.

Light Lab

Alternate version of the Dr. Light's Lab theme.

Wily Battle

Another version of the Wily Fortress boss music. Certain elements from this piece were used in the final version's theme.