In the code entry prompt, push X, Triangle(3), X, Circle, X, Square.
Invincibility
In the code entry prompt, push Square(2), X, Triangle, X, Circle, X, Circle.
All future weapons
In the code entry prompt, push X(3), Triangle, Circle(2), Square, X.
All past weapons
In the code entry prompt, push Circle(2), Triangle, Square, X, Triangle(2), Square.
Quadruple damage
In the code entry prompt, push Triangle(4), Square, X, Circle, Square.
Mission complete
In the code entry prompt, push Square(2), Triangle, Circle(2), X, Square, Triangle.
Level select
In the code entry prompt, push Square(3), Circle(3), Triangle(2). Note: In the PAL version of the game, In the code entry prompt, push Circle(3), Square(3), Triangle(2)
Fight TX Endoskeleton in all battles
In the code entry prompt, push Triangle, Square, Triangle, X, Triangle(4).
50% more health in combat with T800
In the code entry prompt, push Triangle(2), Square, X, Circle, Triangle, Square, Circle.
50% more health in combat with TX
In the code entry prompt, push Square, Triangle, Square, Triangle, Circle, X, Circle, X.
50% less health in combat with TX
In the code entry prompt, push X, Triangle, Square, Circle, Triangle, X, Square, Triangle.
Centipede mini-game
In the code entry prompt, push Circle, Circle, Circle, Square, Square, Square, Triangle, Square.
Or Finish the game to unlock Centipede at the "Atari Games" menu. Note: If it is not unlocked as soon as you complete the game, restart your PlayStation2, reload your game, and recheck the "Atari Games" menu.
Missile Command mini-game
In the code entry prompt, push Circle, Circle, Circle, Square, Square, Square, X, X.
Alternately, in the vet's office on level 13, walk into the small office on the far right side. Approach the computer and push X to play Missile Command. Then finish the level to unlock the game at the "Atari Games" menu.
All FMV sequences
In the code entry prompt, push Triangle, Circle, Square, X, X, X, Triangle, Circle.
All still pictures
In the code entry prompt, push X, Square, X, Square, Circle, Triangle, Circle, Triangle.
View development team
In the code entry prompt, push Circle, Circle, Circle, Square, Square, Square, Triangle, X.