Half-Life PlayStation 2 Cheats

Low Gravity
At the cheat screen enter: Up, Triangle, Down, X, Up, Triangle, Down, X.

Invisibility
At the cheat screen enter: Left, Square, Right, Circle, Left, Square, Right, Circle.

Slow Motion
At the cheat screen enter: Right, Square, Up, Triangle, Right, Square, Up, Triangle.

Invincibility
At the cheat screen enter: Left, Square, Up, Triangle, Right, Circle, Down, X.

Alien Mode
At the cheat screen enter: Up, Triangle, Up, Triangle, Up, Triangle, Up, Triangle.

Infinite Ammo
At the cheat screen enter: Down, X, Left, Circle, Down, X, Left, Circle.