Pause the game and press: Triangle, Triangle, L2, R2, L2, R2, R1, Circle. Now all objects(including enemies), items, weapons, and secret switches will appear on the map.
Map all lines
Pause the game and press: Triangle, Triangle, L2, R2, L2, R2, R1, Square. Now all walls and boundaries will appear on the map for the current stage.
Weapons, Ammunition, and keys
Pause the game and press: X, Triangle, L1, Up, Down, Left, Left(twice). Now all weapons, ammunition for them, and keys for the current level will be available.
Level Select
Pause the game and press: Right, Left, R2, R1, Triangle, L1, Circle, X.
Transparent Walls
Pause the game and press: L1, R2, L2, R1, Right, Triangle, X, Right. Now your character may see through one layer of wall or sprites.