Since I can't submit this in the cheats section because neoseeker hasn't bothered to include one for the PC version, here they are.

Note: These also apply to console versions as well.

you will hear the unlock sound if done correctly and the words to the right such as "EU" "US" or "JP2".
Sonic 1 EU Version:
Up,Z,Down,Z,Left,Z,Right,Z

Sonic 1 JP2/Japanese Version with bug fixes (V2):
Z,Z,Z,Z,Z,Z,Up,Down,Left,Right

Sonic 1 Alt US Version:
Start Sonic 2/3 then exit one of those games then select Sonic 1, and at it's info screen you will see to the right the words "US"

*Edit*
Cheats must be entered at information screen, before you begin gameplay.

In the PS2 version substitute Z button with R2



This message was edited by meman887 on Apr 19 2008.

This message was edited by meman887 on Aug 02 2008.