Looks sweet. Lots of additional animations that I've never seen before, such as when Sonic goes through a loop, you see the sprite scale around, rather than cycling through a few sprites.
Semi-transparent shadow trails of Sonic running real fast and the mobius strip foot animation are also welcome. One is a new thing, the other is a thing I've always liked.
They're not cramming bajillions of characters in. Sonic, Tails, Knuckles, done. Maybe there are secret characters if you collect 100 widgets or something. But keeping the character roster down to minimum and (presumably) keeping the story out of the way of going fast and smashing badniks are plusses in my book. I mean, they didn't say boo about any story this game may or may not have. To me, that's heartening, too. I didn't enjoy it when the story started to dominate Sonic games.
...Seems neat. I likey.