Bust-A-Move 4

Bonus characters
At the main menu, press Up, Down, Left(2), Right, Up, A, B(2), A.

Bonus levels
When "Push Start" appears at the title screen, press A, Left, Right, Left, A. If you entered the code correctly, a game character will appear in the bottom right corner of the screen.

Game Shark Codes

Note: You must have a 2.1 or higher version of the Game Shark to use these codes in a Game Boy Color system.

Infinite Credits -- 01042DD5