Sonic the Hedgehog 2 (8-bit) AutoDemo/Hidden content

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Free movement

Sonic2AutoDemo GG FreeMovement.png

Changing byte 0x0064 to 02 will enable the ability to move around a level freely. Once enabled, hold 1 and press the D-Pad in any direction during gameplay to move Sonic around.[1]

Unused content


Art Description
Sprites that depict Sonic laughing in a rather creepy manner. Purpose unknown.
A frame of Sonic's idle animation from the Master System version of Sonic 1, but altered to make him look happy.
An early skidding animation, which looks closer to those from the Mega Drive version.
Sonic can't die in this prototype, so this death sprite goes unused. It is identical to the final's early death sprite, taken from the Master System version of Sonic 1.
No monitors appear in any level, but graphics for them are loaded at the Sega/title screen.
These button sprites are located within the Under Ground Zone tileset, but aren't used in any Acts.
Under Ground Zone only has downward-facing spikes at this point, rendering these upward spikes unused.
There's nothing that can explode in the AutoDemo, so the explosion tiles that are located within the number/icon sprites are never seen in action.
Blocks can't be destroyed in the AutoDemo, leaving this fragment unused.
The trees seen in the final Sky High Zone and in some prerelease screenshots are present in the ROM, but not actually used at this point.[2]
The 16x16 font from the unused level title cards (see below). Only 8 of the 41 characters get used.

Early title card

Sonic2AutoDemo GG TitleCard.png

Setting ROM address 0x2BA to 03 will sometimes load an early title card on resets. It crashes to a black screen after two seconds.[3]

Build date

Similar to other games developed by Aspect, the game's build date can be located at ROM address $C0:

MS SONIC¥THE¥HEDGEHOG.2 Ver0.00 1991/12/05 Aspect Co.,Ltd


Sonic the Hedgehog 2 (8-bit) AutoDemo, prerelease version of Sonic the Hedgehog 2 (8-bit)
Sonic2AutoDemo GG title.png

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Part of Sonic the Hedgehog 2 (8-bit) development