"This looks like it could be a nice return to form for Sonic, and it appears that there is a mixture of both 2D and 3D platforming."
Did you not play Sonic Colors or the HD versions of Sonic Generations?
Sonic Colors and Generations are very good games and while pretty fun I think they lack what made the classic Genesis titles so comparable to classic Mario titles. Those games did not translate what 2D Sonic was about into 3D. Auto boosting to the point that every enemy means jack and platforming that isn't nearly as satisfying.
I'm glad Sonic is going this route, because while the twitchy constant roller coaster stages are fun, the whole game shouldn't be that and Sonic should not feel like a car. Sonic should feel like a heavier, faster Mario where momentum is built up gradually and you can effectively and easily slow down if you want to.
We now know Sonic basically shifts gears. 1st gear is slow run, 2nd gear is medium run, 3rd gear rolls him up like a spin dash and blasts him off, just like the way it should have been year ago.
Sonic is the only playable character but hopefully Tails and Knuckles are unlockable extras.
Sonic started to get too cool. A BS kind of cool. The games were built around plot and visuals. Soon Sonic stopped rolling into a ball! What the EF is that? Just speed blitz enemies by doing almost nothing? Come on!
I'm optimistic once again about a Sonic game but even colors barely did anything for me. When I look at this though, it really looks like someone is in control of a 2 legged creature and not constantly on an auto rail just auto boosting.