Here are some cheats and tips for the game Samurai Jack: The Shadow Of Aku.
Crystal sword:
Press Left Analog-stick Down + Right Analog-stick Up, X, Circle, Square,
Triangle during game play.
Sketch gallery:
Successfully complete the game under the easy difficulty setting.
Background gallery:
Successfully complete the game under the normal difficulty setting.
Model gallery:
Successfully complete the game under the hard difficulty setting.