HalfLife - Invincibility

Invincibility

At the Cheat Code screen press Left Square Up Triangle Right Circle Down X Start.

Unlimited Ammo

At the Cheat Code screen press Down X Left Circle Down X Left Circle Start.

Unlock Alien Mode

At the Cheat Code screen press Up Triangle Up Triangle Up Triangle Up Triangle Start.

Unlock Invisibility

At the Cheat Code screen press Left Square Right Circle Left Square Right Circle Start.

Unlock Slow Motion Mode

At the Cheat Code screen press Right Square Up Triangle Right Square Up Triangle Start.

Unlock Xen Gravity

At the Cheat Code screen press Up Triangle Down X Up Triangle Down X Start.

GameShark Codes