Super punch
Press:X, L1, R1, O, O, R2 and pac-man's punch will upgrade.
Unlock all levels and mazes
At the menu screen (the one with new game, load game etc) input the following code to unlock all the levels and all of the 3D maze games. Note that the code must be entered quickly.
level select/maze
select left, right, left, right, circle, up