Sonic Adventure 2 is the sequel to Sonic Adventure. It was the final Sonic game for the Dreamcast after Sega discontinued the console. Two new playable characters were introduced, Shadow and Rouge, who would go on to become two of the most recurring characters in the Sonic series. The story features good vs evil: Sonic, Tails and Knuckles attempt to save the world, while Shadow, Doctor Eggman and Rouge attempt to conquer it. The levels are divided into three gameplay styles: fast-paced platforming for Sonic and Shadow, multi-directional shooting for Tails and Eggman, and action-exploration for Knuckles and Rouge.

Dr. Eggman has teamed up with Shadow, a dark hedgehog with a mysterious past, and is aiming once again to rule the entire world with the power of the Chaos Emeralds.