Sonic the Hedgehog Triple Trouble

Sonic the Hedgehog Triple Trouble
Also known as: Sonic & Tails 2 (JP) Developer: Aspect Publisher: Sega Platform: Game Gear Released in JP: November 11, 1994 Released in US: November 15, 1994 Released in EU: November 1994 This game has unused code. This game has hidden development-related text. This game has unused enemies. This game has unused graphics. This game has a hidden level select. This game has regional differences.

Dr. Robotnik is plotting, Nack is ineffectual, and Knuckles is a dick fine upstanding citizen with unflinching moral fiber.

Unused Graphics

Object Art

Artwork	Description
	Knuckles getting hurt/tired while gliding.
	Nack blinking, and holding a red Chaos Emerald.
	A bonus sign using Nack's face.
	Tiles for an unused enemy are loaded in Atomic Destroyer Zone.

(Source: Sonic Retro)

Level Art

Artwork	Zone	Description
	Great Turquoise Zone	There are spikes used "inside", but this outside spike isn't.
	Meta Junglira Zone	Another unused spike and a 30-degree slope.
	Robotnik Winter Zone	A 45-degree slope in front of the stage background, and an outside spring.
	Tidal Plant Zone	Many unused springs. The giant bubbles in this stage make most of these springs useless.
	Special Stage	Several unused slope types, spikes (which don't appear in any Special Stage), and border tiles.

Unused Text

Aspect's standard header for their Sonic games is present at 0xC0:

Sonic & Tails 2	Sonic Triple Trouble
GG SONIC & TAILS Ver 1.00 1994/07/30 @SEGA /Aspect Co.,Ltd	GG SONIC THE HED GEHOG Ver 1.00 1994/08/02 @SEGA /Aspect Co.,Ltd

Error Handler

This game has a generic error handler routine at 0x70 like most other 8-bit Sonic titles, but it's quite a bit more elaborate than the rest of them. Instead of blindly scribbling an error message to VRAM, it performs some fairly extensive cleanup beforehand, loads the needed font graphics and palette, then prints "ERROR" before waiting for 3 seconds and resetting.

What's more, the handler is actually purposely called this time around! When loading a new subscreen, the game uses the target subscreen variable at RAM $D143 as an index into a jump table. If the high byte of the address read from the table is 0xFF—there is a dummy entry of 0xFFFF at index 0x1A, one past the last valid entry, for this purpose—the game will jump to the error handler.

Level Select

Hold Up and power on the Game Gear. In the opening cutscene, press Start the instant Knuckles picks up the third Chaos Emerald. If timed correctly, a ring chime will play, and the level select screen will appear after choosing a character.

Regional Differences

Title Screen

Sonic & Tails 2	Sonic Triple Trouble

The title screen is almost completely different between the Japanese and international versions.

The Japanese version also has an extra option, "3D Stage". It simply starts up the first 3D special stage (allowing a choice of either Sonic or Tails) and resets once it's completed.

However, graphics for this menu option are still in Sonic Triple Trouble, and the option can be re-enabled with Game Genie codes 041-49E-E66 031-31E-E62.

The title screen intro is different as well. In Sonic & Tails 2, Sonic and Tails run across the screen, then the game's logo comes up. In Sonic Triple Trouble, Knuckles jumps onto the title and laughs.