The Portuguese magazine Maxi Consolas, has recently revealed new information regarding Sonic Unleashed in their latest preview. The magazine has confirmed that:

1. Unleashed will have level up system, in which you can enhance and improve Sonic’s abilities, much like an RPG.
2. There will be other playable characters besides Sonic, however they will only be playable via mini games, reserving most of the game for Sonic. Tails has been the only confirmed character as of yet. There where no details regarding how the mini games would play.
3. In addition to the African, Greek, and “High Europe” stages, there will also be levels that take place in China and New York City.
4. Levels alternate between the 3D and 2D perspectives every thirty seconds or so. Camera work is impressive.
5. Good impressions overall. They only complain about the frame rate.

Source: Sega Nerds