Sonic 2 is my favorite... played it for some hundred times
Umm, if you're playing it on the old Sega Mega console (I still have it
) I'll teach you a trick
You know how you get the Yellow Sonic ability if you get all the Gems through the ring tracks...
Well, whenever you do the ones in the first level, reset the console using the Reset Button
Apparently it's as stupid as Warcraft III to not remove the saved information (call it leaks) about the gems... so you'd be able of getting all the gems at first level
(unless it's some other sonic two you're talking about)
Man I felt as such a proud child for finding that out by myself