Then play this! One of the best Sonic games ever that someone made.

http://uploads.ungrounded.net/content.php?id=151706&name=151706_ultimate_sonic.swf&title=ultimate%20flash%20sonic&date=1077685200&quality=b&uj=0&w=350&h=250

Is that an original game that someone made with the Sonic characters and spritework, or is it a flash version of an existing game? Looks very similar (but different) to one I have for my Gameboy SP.

Its an original one that someone made. I found it on newgrounds.com

That is so cool! Use it for a sig.