Goodies option
At the "Press Start" screen, press Triangle, Square, Circle, Left, Square, Triangle, Square, Circle, Left, Square within three seconds. Then, an additional selection will appear at the end of the options menu that allows level selection, all weapons, infinite ammunition, and the ability to view the FMV sequences.
Stage select
Enable the "Goodies option" code. Then at the "Press Start" screen, press Left, Right, X, Triangle, Left, Up within three seconds. If you entered the code correctly, there will be a white screen flash, sound effect, and display of the cheat name. Then, an option that will allow selection of an individual stage within a level will become available. Note: Enabling this code may cause music and graphic problems.
Nakomi mode
At the "Press Start" screen, press Up(2), Down(2), Left, Right, Left, Right, X, Circle within three seconds. If you entered the code correctly, there will be a white screen flash, sound effect, and display of the cheat name. Then, all 3D characters except the Boss will be flattened.
Big head player
At the "Press Start" screen, press Square, Circle(2), Square, Up, Square, Circle(2), Square, Triangle within three seconds. If you entered the code correctly, there will be a white screen flash, sound effect, and display of the cheat name.
Big Head aliens
At the "Press Start" screen, press Square, Circle(2), Square, Up, Square, Circle(2), Square, X within three seconds. If you entered the code correctly, there will be a white screen flash, sound effect, and display of the cheat name. Note: This code does not affect the Boss.
Turbo mode
At the "Press Start" screen, press X, Square, Triangle, Circle, X, Square, Triangle, Circle, L2, R2 within three seconds. If you entered the code correctly, there will be a white screen flash, sound effect, and display of the cheat name. Then, press Circle while playing a game to run faster. Note: This will also use any item currently being held by your character.
Grayscale graphics
At the "Press Start" screen, press X(2), Triangle(2), Square(2), Circle(2), Up, Down within three seconds. If you entered the code correctly, there will be a white screen flash, sound effect, and display of the cheat name.
Sepia graphics
At the "Press Start" screen, press Left(10) within three seconds. If you entered the code correctly, there will be a white screen flash, sound effect, and display of the cheat name.