This is one of the few Sonic games I haven't gotten the True Ending for. Those Time Stone were pretty difficulty to obtain. If this game isn't an emulation as reported, there will be no game saves which will make this a pretty awesome challenge (assuming there's an achievement for it).
EDIT: I should clarify something. The original game (EDIT: on PC at least) DID have the ability to save your game either after each Act or Zone (can't remember). So yes you can reload a save to replay a level again for whatever reason (beating a certain Act in a certain time, going for Time Stone challenges, etc), you just shouldn't be able to save in progress.
Last edited by Veedrock; 11-25-2011 at 01:17 AM.