Sonic Adventure 2: Battle is a Game Cube game that is a remake of Sonic Adventure 2 for the Dreamcast, which is almost universally agreed to be the best 3D Sonic game. Sonic Adventure 2 was the first game to feature Shadow the Hedgehog and Rouge the Bat. Ironically, this game sold better on Gamecube than it did on Sega's own system, the Dreamcast.
The game featured 2 stories: The "Hero" Story, in which the player controlled Sonic, Tails, and Knuckles, and the "Villains" Story, in which the player controlled Shadow, Rouge, and Dr. Robotnik (refered to as Eggman). Amy was, thankfully, not a playable character like she was in Sonic Adventure 1. Sadly, she still apppeared as a NPC.