Rockman Chaos

From Sonic Retro


Fast Facts on Rockman Chaos

Version: 0.02
Last Release: January 27th, 2008
System: Sega Mega Drive/Genesis
Original Game: Sonic the Hedgehog 2 (16-bit)
Credits: Hayate

Rockman Chaos is an "extreme" hack of Sonic the Hedgehog 2 (16-bit) by Hayate. It is a Rockman in Sonic crossover and practically nothing from the original game will be kept other than the bosses, music, last few zones (Sky Chase onwards) and general bits of the engine (e.g. for drawing stuff on screen and playing music). In the game you play as Rockman, battling against Dr. Robotnik. The default sprites for Rockman are the .EXE style ones, but due to popular demand other sprites may be implemented as an option later.


  • Zones - merged the two acts together into one level called "X Area" where X is one word.
  • Overworld - adding an isometric Battle Network-style overworld.
  • Bosses - kept from the original game, but removed from zones and placed at certain places in the overworld in encounters, speaking of which,
  • Encounters - lots of lovely textboxes. I've already written a routine to display these on plane A (in multiple colors ala Sonic Battle, plus flashing colors for emphasis), but I think it'd probably be better on the window plane, if I can figure out how to use that
  • Rings - removed from all levels. There is no equivalent in a Rockman game.
  • HUD - completely removed, and just add a Rockman-style healthbar, plus an extra "power" bar (think Sonic Battle), allowing you to style change when it fills up.
  • Bottomless pits - absolutely none of them, think Metroid.
  • Spikes - If you have only 1 hit point left, you die, but otherwise landing on them takes your health down to 1 hit point.
  • Enemies - shoot them (in all eight directions for once) rather than jumping on them.
  • Bosses (again) - healthbar displayed on screen with much more HP, and varying amount of HP taken off per hit depending on a) where you hit and b) how many bosses you have beaten so far (Robotnik upgrades his ship twice in the game, both times changing its graphics).
  • Monitors - fill health, fill power, take damage, invincibility, super speed, weapon upgrade, weapon/ammo replenishment (last two depend on your selected weapon and do nothing if you have an unupgradable/unreplenishable weapon selected)
  • Springs - horizontal ones gone. Vertical and diagonal ones have significantly less power than they did before, as Rockman is a lot heavier than Sonic.
  • Speed - Rockman moves a lot slower than Sonic as you'd expect, even with the super speed powerup. However, there are various interesting tricks you'll be able to use to go faster than maximum speed for a short while. This game will be one for the TASers.
  • Slopes/curves - Rockman doesn't move with a 360 degree engine, so levels will be edited to remove all loops and sections where you run on a wall or ceiling.
  • Pinball - in the Pinball Area (Casino Night), you can launch a controllable pinball which moves just like Sonic in pinball mode did, which also shifts the screen to center on the pinball, and when you get it to the target, a wall opens allowing you to progress.
  • Emeralds, special stages - completely gone
  • Bonus Area - think Ristar, these are kind of replacing special stages, I don't know what to use as the condition for entry yet, but I guess I'll figure that out later.
  • Ending - once some conditions have been reached, you can go to Golden Palace (from S2OP), which is otherwise a typical level ending in a boss fight against Knuckles, then you go to Sky Chase with Rockman piloting the Tornado, and everything from that point onwards is just like original S2.
  • Weapons/abilities - awarded after clearing a boss under certain conditions
  • Two player mode - race as in original S2 or battle each other in a small arena - and I swear I will find a way to enable splitscreen in water levels!


Emblems are a little like those in Sonic Adventure and Sonic Adventure 2. There are a hundred in total. You collect them for doing various things, and new features are unlocked when you collect a certain number of them. You can obtain:

  • Sixty for completing tricks
  • 28 for completing areas
  • 12 for completing bosses


Gameplay in Rockman Chaos is quite complicated but should be easy to get used to. The basic controls are:

  • Left/right - move (or crawl if crouching)
  • C button - jump
  • B button - shoot
  • A button - grab (if standing next to an object/wall) or build power (if not; this works like Sonic Battle's L-button and only takes effect if you have already unlocked the powerbar)
  • A button + direction - pull; release the A button before the direction to do a horizontal wall-jump which lets you boost
  • Down - crouch (in the Panel Setup screen you can choose whether you must hold down to crouch/crawl, or just press down to crouch and then press up to un-crouch)
  • Double-tap Up - enter shooting lock mode (while on ground); left and right can then be used to aim and B to shoot
  • Any direction(s) + B - aim and shoot (while not in shooting lock mode)

After unlocking the powerbar (this happens when you unlock the first style change, which are each rewards from bonus stages), you can then raise the value in the powerbar either by using the A button, by absorbing certain attacks or in a few other ways (e.g. power monitor). Once it is full you automatically style change and stay style-changed until it runs out again. The style you use you must set beforehand in the Panel Setup screen, and cannot change it once you have entered style-change mode (though if the bar runs out, you can change it again before the next style change even if it is in the same area). While in style change mode the bar drains at one block per four seconds (a "block" is four pixels of the powerbar; the default size is eight blocks and you can increase it with upgrades found throughout the game). Of course you can still keep filling up the bar ala Sonic Rush to keep the mode for an extended period of time. Style changes are similar to Super Sonic; all style changes (there are four) make Rockman faster and invulnerable to touch damage (though you cannot kill/harm enemies just by touching them in this mode), and each style also has its own individual ability (see below).

Bonus areas

There are 16 bonus areas in the game. The first four can be accessed no matter what, the middle eight each require you to have a particular weapon (of the first eight weapons) before you can access them and the last four require you to have achieved a particular Style Change. To get to a bonus area, you need to go into any one of the eight normal areas and find the hidden bonus area warp panel, which will take you to a random uncompleted accessible area, or, if you have completed all accessible areas, will let you select one. Once you've used the warp panel, it will be unusable until you next begin playing that area. Thus all bonus areas can be accessed and complete before you first beat the game, but you must repeat at least one normal area before you can complete all 16 bonus areas. Each bonus area has an associated element (for the last twelve, these are the same as the weapon or style change element required to access them), and there are four of each element. When you complete the first three bonus areas of an element, you obtain that element's style change. Completing the last four bonus areas rewards you with a bigger health or power bar.


The following is a list of weapons, which are obtained from beating bosses.

All the bosses are the same as from original Sonic 2, except that the EHZ and MCZ bosses are switched over (it makes sense because EHZ is now Cavern Area).

A/E/W/H are the elements (aqua/electric/wood/heat). There are deliberately equal numbers of each and no "normal" types (only the rockbuster itself is "normal") so this is why it may seem that some don't really fit.

  • (ARZ) RA: W / Arrow Shooter - Works like the magnet beam from the first NES Rockman game
  • (CNZ) PA: E / Zap grapple thing - A combination of Rayman 3's blue can weapon and ninja rope from Worms
  • (EHZ) CA: W / Sonic - Gives Rockman the ability to turn into a ball and roll like Sonic by holding B (he can also substitute for PA's pinballs with this, which makes the boss much faster)
  • (HTZ) HA: H / Flamethrower - self explanatory
  • (MCZ) IA: A / Ice Beam - Just like Metroid's Ice Beam
  • (OOZ) OA: A / Oil - Might seem kind of weird at first, but you can coat the ground with oil and slide on it to gain speed
  • (CPZ) LA: H / Bomb - Bombs either thrown or laid
  • (MTZ) MA: E / Orbs - Protects you like the MTZ boss' orbs, and they can be fired at enemies as a homing attack
  • (HPZ) GP: A / Saber - self explanatory
  • (WFZ) WF: E / Spinny spike platform thing - You stand on a spike platform from the WFZ boss, and can control it like S3 MGZ's spinny platforms. Obviously you can attack enemies below you with it. This is pretty much an upgraded arrow shooter/magnet beam
  • (DEZ) DE: W / Silver Sonic - An upgraded form of Sonic, pretty much the same except you also have the spikes, making you practically invulnerable
  • (DEZ) DE: H / Missiles - OHKO homing attack

The last two are deliberately uber-powerful, because you don't get them til you beat Silver Sonic/the final boss respectively, at which point you'd have beaten the game anyway, so they're pretty much a reward for the sake of time-attacking.

Since the first 8 zones can be completed in any order, time attackers will be challenged as the various weapons may help in various other zones.

Each style change also counts as a weapon; the following four are available:

  • Heat Guts style - triple power on all of your attacks
  • Wood Shield style - the fan is now your weapon which by pressing B you can either use to hover/fly or to repel enemy attacks - useful in some bosses
  • Elec Brother style - by pressing B you immediately start boosting (this is an attack regardless of whether you are style-changed)
  • Aqua Custom style - similar to S3K's water shield and Metroid's gravity suit, allows you infinite air underwater and allows you to move at normal speed (i.e. superspeed from the fact you are already style-changed) underwater

Track listing

So far: (ID - original use - new use); struckthrough tracks indicate a replacement song has been added to the game

  • 01 - 2P Menu/Results - Overworld
  • 02 - Emerald Hill - Cavern Area
  • 03 - Mystic Cave 2P - Ice Area
  • 04 - Oil Ocean - Ocean Area
  • 05 - Metropolis - Setup Panel
  • 06 - Hill Top - Hill Area
  • 07 - Aquatic Ruin - Golden Palace
  • 08 - Casino Night 2P - Pinball Area
  • 09 - Casino Night - Unused
  • 0A - Death Egg - Metallic Area
  • 0B - Mystic Cave - Encounter
  • 0C - Emerald Hill 2P - Ruin Area
  • 0D - Sky Chase - Sky Chase
  • 0E - Chemical Plant - Lab Area
  • 0F - Wing Fortress - Wing Fortress
  • 10 - Hidden Palace Evening Star - Versus Menu
  • 11 - Level Select Sonic 3 Data Select - Level Select
  • 12 - Special Stage - Bonus Area
  • 13 - Boss - Boss
  • 14 - Final Boss - Final Boss
  • 15 - Ending - Theme of Silver Sonic
  • 16 - Super Sonic - Unused
  • 17 - Invincible - Invincible
  • 18 - Extra Life - Unused
  • 19 - Title Screen - Sonic Retro screen
  • 1A - Act Clear - Sonic 3 Act Clear - Area Clear
  • 1B - Game Over - Game Over
  • 1C - Continue - Unused
  • 1D - Emerald Obtained - Emblem Obtained
  • 1E - Credits - Credits
  • 1F - Drowning - Drowning


Download.svg Download Rockman Chaos
File: Rockman (964 kB) (info)
Current version: 0.02