Pause game play and press X, Triangle, R2, Triangle, X, L2, R2, Down, L2, Square, Right. A beep will confirm correct code entry. Note: This code may only be enabled three times during the entire game.

Pause game play and press Up, Right, Triangle, Circle, Down, Left, X, Square. A beep will confirm correct code entry. Note: This code may only be enabled once per level.

While playing, pause the game and press L2, L2, R2, R2, Up, L1, Up, R1. A beep will confirm the code. Note: This code may only be enabled five times during the entire game.

Enter the following codes at the title screen.

Los Angeles: Circle, Circle, R2, R2, Left, Right, Up, L2, L2, Triangle
Los Angeles 7: Circle, Circle, L2, L2, Left, Right, Up, R2, R2, Triangle
Las Vegas: Square, Square, L2, L1, Up, Down, R1, R2, Left, Right
Las Vegas 7: Triangle, Triangle, L2, L1, Up, Down, R1, R2, Right, Left
San Francisco: Circle, Square, L2, R1, Triangle, L1, R2, Down, Up, Left
Houston: L2, L1, R1, R2, Circle, Left, Left, Triangle, Right, Right
Washington: Circle, Circle, L1, R1, L2, R2, Left, Right, Triangle, Square
Florida: L1, R1, Square, Circle, R2, L2, Up, Triangle, Down, Down
Nebraska: Square, Square, Left, Left, Square, Circle, Circle, Up, Up, Square
Moon Base: R1, R1, L2, R1, Square, Triangle, Triangle, Left, Right, R2.

Pause game play and press Down, Square(3), Circle(2), Up, Right. A beep will confirm correct code entry. The M-16 will now have 999 rounds of ammunition.

Pause game play and press Left, Triangle. L2, Right, R1, Circle, R1, Down. A beep will confirm correct code entry. Note: This code may only be enabled three times during the entire game.

Pause game play and press Left(2), L1, R2, Square, R1, Right(2). A beep will confirm correct code entry. Note: This code may only be enabled five times during the entire game.

Pause game play and press Triangle, X, Triangle, X, Triangle, X Square, Circle, Square, Circle, Up, R1. A beep will confirm correct code entry. Note: This code may only be enabled three times during the entire game.

Pause game play and press L1, R1(2), L2, R2, L2, Circle, Triangle. A beep will confirm correct code entry. Note: This code may only be enabled 100 times per level.

Press Square(4), Circle(3), Square(2) at the main menu.

Press L2(2), R2(2), L1, R1, Square, Circle, Up, Down at the main menu.