But I'm still playing the damn game. I figured I would have been done with it after a week. Imagine my surprise two and a half weeks later...

I'll just say this for now: it's a hell of an improvement over Sonic '06. Though, if you happen to be a PS2/Wii owner, I can't comment on those versions, since they were made by another developer, and I've heard that the PS2/Wii and 360/PS3 versions are quite different.