The most under-rated I've seen. Learn how to rate games Gamespot.
The Sonic stages are the best part of the game the are fast platforming and you don't6 want to stop playing them. they never get old and you go faster then any sonic game on the next gen systems. the boss fights are cool and nothing about this game feels lazy at all.
The werehog stages aren't as good, don't get me wrong the are pretty fun. the only down side is you don't go fast at all. I like that he can learn different move sets and become stronger but the enemies don't stop coming. Also you get a Rank S without tring you can go to a enemy and do a combo on him perfectly and it gives you a major boost in your score.
the only thing i hate is the hub world this terrible, terrible hub world where you aimlessly walk around talk to people for no reason and the people in these hub worlds are useless. when you talk to them nothing benefits you in any way.
Overall this game deserves a 9.7/10