This is one of those games that should be bound to be a big game, especially this is Sonic's birthday celebration. Sadly, this birthday was a bust, because it does bring everything it said, but it comes with flaws that could cost it. BIG TIME.
First off, glitches are extremely common, and the controls are sort of funky. Plus, lighting is also poor, and that can lead you to fall off the road into a pit of nothingness (for example, Flame Core). But the big problem is LOADING SCREENS. If you want to know how much this is irritating, let me give you an example. When you are asked to do a challenge in town, you talk to the guy, loading screen. You say yes, loading screen. You do the challenge, then a loading screen. The guy thanks you, loading screen. You are paid, and one shiny penny for what happens next. Coupled with the fact they are incredibly long, this game is pretty bad.
The good things you could say, though is that the music is diverse, and the characters are all so unique.
Score: 4/10
The Good: Soundtrack, the beautiful graphics, and... uh...
The Bad:... The storyline is awkward, and LOADING SCREENS SUCK.
The Purely Awesome Character: Ya gotta love Silver the Hedgehog.