Description: [Xbox Live Arcade] The blue hedgehog and the red echidna were sworn adversaries in Sonic 3, but in the platform adventure Sonic & Knuckles, Knuckles realizes that he's been just a pawn in the schemes of Dr. Eggman (aka Dr. Robotnik). Knuckles, the former adversary, now supports Sonic to chase the common enemy, and each must use their strengths to acquire the priceless Master Emerald and save Angel Island. Sonic or Knuckles: Play as Sonic and let loose on Dr. Eggman wth amazing new powers, or play as Knuckles and tackle Dr. Eggman with bare-fisted attacks, high speed glides, and wall-climbing abilities. New adventures: Eight new zones and two different adventures await. Combine games: For the first time since the SEGA Genesis, combine with Sonic 3 to play as Sonic, Knuckles, even Tails, and unlock new secrets! Combine it with Sonic 2 and play with Knuckles and all his signature moves. [Sega]