Zifei just sent me this info over IM but I was away at the time and couldn't get more details. I'll try to find out more ASAP.

- The game's playable characters are Sonic, Shadow, Tails, & Knuckles. All stages will be optimized for Sonic and Shadow. Tails and Knuckes will use these stages in their respective unique ways.

- Next step in camera system evolution or as Naka-san bluntly put it: "The best camera system ever seen in any platformer ever."

- GameCube and X-Box.