-2 goals: entertain with trademark speed and more-refined gameplay in 2D and 3D; new actions for Sonic
-Wii stages share the same themes as the other versions, but different designs to take advantage of the remote. Helped by Sonic Advance 2 and Sonic Rush teams
-Same actions in different versions: buttons for basic actions, certain actions involve motion control
-Interactive combat sequences using motion sensing in remote and nunchuk
-Quick Step (evade obstacles without slowing), Sonic Boosts (hyperaccelerate/blow up objects)
- Action-Chaining: earn more energy by stringing together actions leading to special moves and shortcuts
- QTE for branching paths
- No passage of time during levels - day and night cycles are fixed to certain events/locations
- Originally envisioned as Sonic Adventure 3
- No multiplayer or online modes