Sonic the Hedgehog 3

Sonic the Hedgehog 3
Developer: Sonic Team, Sega Technical Institute Publisher: Sega Platform: Genesis Released in JP: May 27, 1994 Released in US: February 2, 1994 Released in EU: February 24, 1994 This game has unused areas. This game has unused playable characters. 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 prototype article This game has a bugs page This game has a prerelease article

Sonic the Hedgehog 3 is the third game in the 16-bit Sonic trilogy and the first game with the redheaded echidna, Knuckles. It was originally one big game, until it split into two due to time constraints and cartridge costs. The second half of the game is its direct sequel, Sonic & Knuckles.

Level Select/Debug Mode

To access both a level select and the game's debug mode, press Up, Up, Down, Down, Up, Up, Up, Up after the SEGA logo screen fades to black, but before the title screen appears. The timing is fairly tricky; you'll hear the ring collection sound if you did it right. Alternatively, you can activate the Sonic 2 menu (see below) and enter Sonic 2's level select code (19, 65, 09, 17).

To find the level select on the title screen, simply press Up to reveal "SOUND TEST", and press Start. To activate debug mode, select a file/level, hold A and press Start, and keep holding A until the level begins. You can also hold C and press Start to highlight high-priority background tiles (tiles that overlap Sonic and other sprites).

While in debug mode, you have access to the following:

• Invincibility
• Infinite time
• Debug coordinates (in place of score)
• Sprite counter (in place of time)
• Placement mode: Press B to enter placement mode, which allows you to move Sonic anywhere in the level with the D-pad and place objects from a predefined list (not all objects may be available in a given level). In this mode:
  • Press A to move forward one object.
  • Hold A and press C to move backward one object.
  • Press C to place the object.
  • Press B again to return to normal gameplay.
• Character animation viewer: Hold C and press B to rapidly cycle through all available animation frames for the current character (pause the game and use frame advance to view individual frames). Press B again to return to normal gameplay.
• Pause options:
  • Press A to go back to the level select.
  • Hold B to progress the game in slow motion.
  • Press C to advance one frame.

In addition, if you die, press B to enter placement mode, and then press B at a safe spot to revive yourself. However, trying to place an object in this death state will freeze the game. Additionally, do not enter debug mode at any point where Sonic's sprite rotates (such as while standing on the red-and-white cylinders in Carnival Night Zone) or the game will crash.

Alternatively, you can use the Game Genie code AA6T-AAXC to access the level select.

A third way to unlock the level select menu (if you don't mind risking the long-term health of your console and cartridges) is to load up Sonic 2, unlock its level select (19, 65, 09, 17 in the sound test), swap the cartridge with Sonic 3 without turning the power off, and then press Reset. This works because the RAM variable that unlocks the level select is preserved when you reset the console (Sonic 3 was built upon Sonic 2's source code, and thus shares a number of RAM variables).

Gumball Machine Bonus Stage

If you want to access the Gumball Machine bonus from the level select, don't bother choosing anything from "Bonus", as they don't work. Instead, select Act 2 in the third "2P VS" entry and you'll be sent there. Once you exit the stage by falling off the bottom of the playfield it will repeat, but the title card will glitch and say "DOIL#S S#AGE," with the "#" symbols representing garbled tiles. When you pause and return to the level select, the menu will appear glitched.

Crazy Checkpoint Glitches

If you activate a checkpoint in any act, return to the level select, then load a different zone/act, a massive amount of crazy glitches will occur. For instance, the title card will be wrong and you will spawn in weird places that can sometimes kill you instantly or crash the game, and incorrect music may play at the end of the act.

Secrets

The level select menu shows us what the level order could have been if Sonic 3 was not split into two games. The Sonic 3 zones are in their normal places, but Flying Battery from Sonic & Knuckles is listed between Carnival Night and Ice Cap. Following Launch Base are Mushroom Hill (which was apparently Mushroom Valley) and Sandopolis, but neither of those can be selected.

According to commentary from the Sonic Jam strategy guide, Ice Cap was meant to follow Flying Battery as Sonic was supposed to break down the zone's door and use it as a snowboard. It also mentions that Flying Battery was meant as the eighth zone, with Ice Cap being the ninth. There's also a variety of unused songs, all from Sonic & Knuckles, in the sound test.

Further, all the graphics here (including the level icons) are recycled from Sonic the Hedgehog 2, and the icons are shown in the Sonic 2 order, such as Emerald Hill's icon for Angel Island and Casino Night's icon for Carnival Night. Interestingly, the second "2P VS" entry shows the unused Hidden Palace icon from the Sonic 2 prototypes.

Red Revolving Spheres

This is a spinning mass of red spheres, placeable by debug mode in the first half of Angel Island Act 1. The spheres look similar to those appearing in the game's special stage, but the object itself seems to have no apparent gameplay purpose. When it is placed, many palette and VRAM complications occur in the level, and the game will lag. Player 2 can manipulate this object.

• Up - rotates the object vertically.
• Right - rotates the object horizontally.
• Down / Left - moves the object up or down.
• A / C - changes the object's size.
• B - rotates the object sideways.
• Start - toggles automatic rotation.

Knuckles Leftovers

Some data for Knuckles as a playable character seems to still exist in the game. LocalH has created Game Genie codes ASCA-AAHC + ASCA-BA9Y to allow you to "select" Knuckles as your character. You will play as Sonic, but have Knuckles' character select, continue icons, and level-clearing text. The end signpost will also feature Knuckles, though the image uses Sonic's blue palette.

• 

  So, does this mean we can play as Knuckles without Lock-On?

• 

  Sonic?! What the devil are you doing here?!

Flying Battery Zone

As mentioned earlier, Flying Battery would have been played between Carnival Night and Ice Cap, but when the game was split into two that zone was moved into Sonic & Knuckles to give it more levels. Still, there's some leftovers in Sonic 3 – a data select icon, its music, and even its bosses!

While you can access Flying Battery by way of PAR codes (FFFE10:0400 for Act 1 and FFFE10:0401 for Act 2), it will be corrupted with Ice Cap tiles appearing all over the place. However, you need to do this in a specific way because alone, these codes will crash the game when trying to access that level data.

While you can use codes to access other unused zones (such as Lava Reef), those will crash the game.

To do: Add which codes access which unused zones. Document how far the game gets when trying to access the unused zones before it crashes. Post a savestate here.

Sonic 2 Options Menu

By setting the game's screen mode to $24, you can access the Sonic 2 options menu in Sonic 3! Alternatively, you can use the patch code FFF600:2400 or hack the menu back in yourself.

As all the options here are selectable normally through other means in Sonic 3, the only real benefit of this is entering the Sonic 2 level select code to access it in Sonic 3.

Unused Sprites

Artwork	Name	Description
	"Bored" Animation	Sonic in his signature "waiting" pose, but instead of pointing towards the direction he's facing, he falls asleep from boredom instead. Never used in-game.
	"Whistle" Animation	Sonic whistling. Not used in-game. Speculation reveals that this animation may have been paired with a "Help-Item" mentioned in a German magazine article. Sonic would have broken the monitor, used the whistling animation, and then Tails would fly in from offscreen to carry Sonic around as he pleased, similar to Player 2 controlling Tails while holding Player 1. A whistle sound which is probably related to this can be heard when breaking S-monitors and at the beginning of Doomsday Zone.
	Unused 2P Knuckles Sprites	Unused Gliding/Climbing animations exist for Knuckles in two-player mode, even though he doesn't have the ability to glide or climb while in two-player mode.
	Leftover Continue Animation	Leftover animation from the continue screen in Sonic the Hedgehog 2.
	Mini Death Egg	Smaller rendition of the Death Egg. It seems to be part of a Death Egg hologram projector, which itself was unused in Sonic & Knuckles.
	Diagonal Penguin Sprites	Diagonal frames of the penguin badnik from Ice Cap Zone. These can be seen for a split second, if you place a penguin on the large hill at the beginning of the zone using debug mode.
	Unused Eggman Sprite	Unused running frame where Eggman has a different facial expression.
	"Surfboarding" Animation	An alternate animation for the intro. At one point, Sonic would have been surfboarding to Angel Island, rather than going Super Sonic. Interestingly, Sonic looks like his Sonic 2 incarnation. The surfing Sonic sprite can be placed in AIZ1 via debug.
	Surfboard	These sprites were probably used when Sonic jumps off the board.
	Eggman flying away	An unused Eggman object discovered by Nemesis. It appears to be nothing more than Eggman flying away towards the horizon. Its purpose is unknown.
	FBZ Data Select icon	An unused save file icon for Flying Battery Zone before it was re-ordered to be in Sonic & Knuckles, which is different than the corresponding icon in Sonic 3 & Knuckles. You can view this icon in the PC and Genesis versions by hacking the save data to access level slot $04, or by using the PAR codes 00C324:601E and 00C338:6002 to view it in a completed game save slot while scrolling through the levels.

(Source: Sonic Retro)