Check out the new Hands-on Preview at PS3Fanboy:
"Sonic has had a hard time since he discovered the third dimensions. Not only is he now chubbier, but his adventures in 3D-land have been met with lukewarm reception. The general consensus is that the last great Sonic game was on the Mega Drive. With Sonic Unleashed Sega are hoping to reinvigorate the franchise with a focus on speed and platforming, as well as evolving the character (literally) into something unique."