Sega is gearing up to release Sonic 2 this November for both Android and iOS. The game will feature updated graphics and sound, along with a few other goodies.
Other titles Sega is currently working on to release are as follows..
Sonic and All-Stars Racing - Platforms: iOS, Android - Release Date: Winter 2013
Demon Tribe - Platforms: iPhone, iPad, iPod Touch - Release Date: Winter 2013
Rhythm Thief and the paris Caper - Platforms: iPhone, iPad, iPod Touch - Release Date: Early 2014