Mega Man IV

Mega Man IV
Also known as: Rockman World 4 (JP) Developer: Minakuchi Engineering Publisher: Capcom Platform: Game Boy Released in JP: October 29, 1993 Released in US: December 1993 Released in EU: 1993 This game has hidden development-related text. This game has unused enemies. This game has unused graphics. This game has unused music. This game has debugging material. This game has a hidden sound test. This game has a hidden level select.

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 GameShark 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. Note that this screen is not using the same screen resources as the end of the game, but a completely different copy of the same data.

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

If the GameShark code is being used, be sure to disable it once you've entered the menu.

• TOAD-TOMS: Marks the appropriate boss as defeated and gives you their weapon. Self-explanatory except for TOMS, which is Charge Man.
• BLDA: Marks the Wily Tank stage as completed.
• BKBA: Marks Ballade as defeated and gives you the Ballade Cracker weapon.
• BEAT, WILY: Gives you the appropriate letter(s).
• ME: Number of mini E-Tanks. Every fourth mini tank gives you a full E-Tank.
• WP: Number of Weapon Tanks (Max 4).
• SP: Super Tank toggle.
• EB: Energy Balancer toggle.
• PC: Number of P-Chips. This value goes in fours, so the maximum value is 996.
• ZA: Number of lives.
• BKI: All weapons toggle. NL is OFF, and FL is ON. Note that this does not mark all of the bosses as defeated.
• HERAZ: Unlimited Tanks toggle.
• 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.
• CNTNUPT: Checkpoint variable. 00 is the start of the level, 01 is the midpoint, and 02 is the last checkpoint.
• 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.
  • 01: Toad Man.
  • 02: Bright Man.
  • 03: Pharaoh Man.
  • 04: Ring Man.
  • 05: Crystal Man.
  • 06: Napalm Man.
  • 07: Stone Man.
  • 08: Charge Man.
  • 09: Wily Tank.
  • 0A: Ballade.
  • 0B: Ballade—Entrance.
  • 0C: Wily Spaceship—Interior.
  • 0D: Wily Spaceship—Teleport System.
  • 0E: Wily Capsule Fight.
  • 0F: Got Weapon screen.
  • 10: Dr. Light opening scene.
  • 11: Wily Tank destruction.
  • 12: Guard Satellite.
  • 13: Wily Spaceship—Exterior.
  • 14: Wily Machine #4 cutscene.
  • 15: Wily Machine #4.
  • 16: Escape from Wily Spaceship.
  • 17: Wily Spaceship destruction.
  • 18: Robot Master demos.
  • 19: Thank You For Playing screen.
  • 1A: Debug intro.
  • 1B: Wily Spaceship—Before Wily Machine #4.
  • 1C: Wily Tank attack.
  • 1D: Wily Saucer cutscene.
• 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.

• SNDNO: Sound test.
• EXIT: Exits the debug menu. This will discard any changes.

(Source: BSFree (sprinter_h))

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

(Source: Original TCRF research)

Unused Enemies/Objects

Cutting Wheel

Object ID: $01
This leftover enemy from Mega Man: Dr. Wily's Revenge works exactly the same as it did in Mega Man III. Which is to say, not very as its proper code is still missing and it despawns immediately. On top of that, its graphics have also been cut down to a single tile.

Unknown Object

Object ID: $02
This strange object uses a tile from Mega Man's diving animation and animates alongside him when charging a buster shot. It crashes the game instantly when touched, probably because its code was removed.

Test Animation

Object ID: $05
A test object used to debug the Guard Satellite's animations. Pressing B will toggle between opening and spinning animations. When loaded, this object replaces the life icon with "PN" and some numbers that probably correspond to the animation sprites. Interestingly, it uses an early version of the Guard Satellite sprites.

Animation 1	Animation 2

Drill Enemy

Object ID: $44
A simple drill enemy, very similar to the also-unused Drillun from Mega Man: Dr. Wily's Revenge. Unfortunately, despite its sprites existing and the game loading them properly, it doesn't seem to have any coding left over.

Unused Graphics

Mega Man

Gemini Laser

Two tiles that make up the sprites for both the horizontal and diagonal Gemini Laser. Gemini Laser was a robot master weapon in Mega Man III, but not in this game.

(Source: Rabbid#4240)

Enemies

Guard Satellite

Early	Final

Found near the hud font it is possible to see an early version of the Guard Satellite, its shading is much lighter than the final version.

Ratton

Unused	Used

Part of Ratton's paw is missing from this game by mistake, although his sprites exist.

Fonts

Debugging Font

Some unused tiles that were possibly used as part of debugging tools.

This font was originally used for a Guard Satellite test animation, to show the animation ID.

Unknown Font

A font of unknown purpose that looks very similar to the one found in the Test Animation and Debug Menu, although it is much more complete, even having lowercase letters and some symbols! Strangely, its graphics are in 1BPP format.

Others Graphics

Dr. Light Icons

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.

(Source: Original TCRF research)

Lightning

Near Wily's sprites you can see some lightning graphics that are not used, possibly at some point in the development the original idea for the cutscene of Wily's fortress was very similar to that of Wily's castle from Mega Man III.

Select Stage (Dr. Wily)

These sprites would probably be used when we finish this stage, although it is possible to go to the previous Select Stage, we cannot go back to the stage where we fight Guard Satellite.

Select Stage (Ballade)

These sprites will probably be used when we finish this stage, although we don't go back to the Select Stage after we defeat Ballade.

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 6×6 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.

(Source: Original TCRF research)

Unused Damage Values

Modifying the game to have all weapons earlier than normal results in some interesting damage data that would otherwise go unused, however this only applies to the two bosses in question:

Notes:

• When using the Ballade Cracker weapon on Guard Satellite it will take 2 damage.
• When using the Crystal Eye weapon on Guard Satellite it will take 1 damage.
• When using the Napalm Bomb weapon on Guard Satellite it will take 1 damage.
• When using the Power Stone weapon on Guard Satellite it will take 1 damage.
• When using the Ballade Cracker weapon on Ballade he will take 1 damage.

Unused Music

To do: Get new rips of these tracks from a more up to date emulator.

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.

(Source: Bean1227)

Regional Differences

Title Screen

Japan	US