Sonic Advance 3
  
GBA
  

Secret Stage: 


Beat every special stage, then go to the main menu and press Up, L, Down, R, Right, Left.

Play as Knuckles:


Beat the Sunset Hill
Zone Acts.





Play as Amy:


 Beat the Toy Kingdom
Zone Acts.





Play as Cream:


 Beat the Cyber Track
Zone Acts.



Thanks to Revolution readers Dingledong and Mr. Larry!