The 2nd episode of sonic 4 has being announced by Sega and with this announcement came the reveal of some new characters and changes from episode 1.

Episode 2 will see the Sonic 4 storyline expanded with new areas and new challenges to boot, Sonic’s sidekick Tails will make his debut in Sonic 4 and a Metal Sonic will appear as this episodes main bad guy. Along with these additions there will be new character animations along with a reworked physics engine. Most of these changes have come around from Sega listening to fan feedback of episode 1.

Along with the announcement came a teaser trailer which can be seen below.

Sonic 4 Episode 2 is due for released sometime in 2012 and will available on Xbox 360 (via Xbox Live Arcade), PlayStation 3 (via PlayStation Network) and mobile devices which use the App Store, Android Market and Xbox Live on Windows Phone 7.