IGN gave Sonic 4-2 6.5.
Here are the closing comments for 4-2
When it was first announced to be in development back in 2009, the promise of SEGA's "Project Needlemouse" seemed incredible – it's no wonder fans of the Sonic franchise got their hopes up so high. Episode I then came along and, for many, failed to deliver on that potential. Episode II is a better game than that one was when it comes to the fans' key criticisms, but yet this second – and final – installment of Sonic the Hedgehog 4 still seems bland. Buy it and enjoy it as much as you can if you're a longtime Sonic follower. Just don't get your hopes up too high again. Sonic the Hedgehog 4, once more, has not been the true second coming of your hero.''
...I understand they're two different reviewers but this is just stupid. OR, it's just that IGN is overall unreliable. Yours to decide.