Samurai Jack: The Shadow of Aku
  
Gamecube
  

Crystal Sword:


  During play, hold the analog stick Down + c-stick Up, then A, X, B, Y.
Sketch Gallery:


  Beat the game on Easy.

Background Gallery:


Beat the game on Normal.
Model Gallery:


  Beat the game on Hard. 
  
  

Thanks to Revolution reader Samurai Bob!