To  enter  these codes, pause the game, and hold L1 and L2 for 10
seconds. While holding down L1 & L2 press the following:

Invincibility:
     Square, Down, Down, Square, Down, Down

Maximum Weapons:
     Down, Right, Down, Right, Triangle.

Skip Level:
     X, R1, Triangle, R1, Square, Circle, R2, R2, X, Square, Triangle,X

More Smart bombs:
     R1, R2, X, Triangle, Square, Circle, R1, R2, Circle, Circle, Square

More Lives:
     Left, Down, Right, Triangle, Square, X, Circle.

Ammo Refill:
     Down, Right, Circle, Left, Right, Circle.

Health Refill:
     Left,  Right,  Left,  Down, Down, Up, Triangle, Circle. or Right,
Right, Left, Down, Down, Up, Triangle, Circle.

Extra player on the character screen:
     R1, R2, Select, Start

Level select:
     Up,  Right, Down, Left, Triangle, Circle, X, Square, X, Triangle,
Square, Circle.

Weapon Power-up:
     To  enhance  the  carnage, pause the game and hold L1 + L2 for 10
seconds.  With  these  buttons  held,  press Down, Right, Down, Right,
Triangle.  From  here  on  you  can  power  up by pausing the game and
selecting the Power option that appears.

Play as bloody body (glitch):
     Put  the  healing code in first. When you die, pause the game and
go  to  healing.  Click on it, and you will play as a bloody body. You
can't get a key or shoot though.