Metal Sonic will take on the roll of antagonist, and the charming Tails will return to reprise his status as Sonic's sidekick. Metal Sonic and Tails are generally regarded as two of the more enjoyable additions to the Sonic roster, so there shouldn't be too much complaining there. And seriously, if you're complaining about these guys, you need to relax.
Additionally, Episode 2 will feature new graphics and physics engines. The latter should be especially pleasing to gamers who hated the way Episode 1 handled. What was wrong with the physics engine in Episode 1? In my opinion, absolutely nothing. In any case, Sega will be reverting to something closer to the Genesis games, which should calm you angry, angry people down.
Episode 2 is slated for launch in 2012. The game will make its way to Xbox 360, PlayStation 3, iOS, Android, and Windows Phone 7. You can check out the interview on YouTube and get the skinny on the upcoming Sonic title.