I've gathered a few:
*Sonic seems to have a smoother control
*The new enemies, although they seem to replace Jetty-syns, they're still in CEZ
*Completely new objectives for unlockables, and now adventure example must have something REALLY interesting...
*FMOD is now used for sounds, making it sound BEAUTIFUL!
*There is now "Ring Toss" and "Ring Toss - Normal" control options in setup controls
I still have yet to play multiplayer, but I bet there are some new maps.
Also, what exactly does "orderpizza" do?