Used to play this alot back when I was younger.
I enjoyed it much better than some points of the real game, as in the full game you have to collect all emeralds with EACH and EVERY individual character to unlock another to get in super sonic, let alone the special rings to do the special stages....
Sorry for rambling, but that crap was annoying, surprised I actually beat it. lol
Anyways, Ultimate Flash Sonic is my childhood... Or my teenhood, more likely. lol