When fighting against Metal Sonic defeat him in the first round,and in the second round turn sonic in to super sonic by pressing ... and he'll change to Dr. Eggman. Press A to play as Dr. Eggman.

Sonic’s enemy Doctor Eggman, or Dr. Ivo Robotnik (Jim Carrey), is joined by his grandfather Professor Gerald Robotnik and Shadow to take control of the Eclipse Cannon. However, with some classic ...