Power shotgun:
Pause the game and press Triangle, Circle(2), Square.

Level select:
Enter G0LVLxx, where xx corresponds to the number of the desired level, as a password. The phrase "Cheat Activated" will appear after the "Accept" option is selected to confirm correct code entry. Select the "Quit" option and start the game with just the pistol. Note that starting at level 34 will display the end sequence of the game.

Soundtrack:
Place the game disc in an audio CD player and play the even numbered tracks to hear music from the game.

Level 4: Weapons:
Find all of the ID Tags you get from the security guards. You can eliminate them with the pistol. They will drop 9mm clips if you need ammunition. Once you have found all of the tags, find the battery in the blue lit room with some alien warriors. Use the shotgun to dispose of them, then return to the room where the security guards are. Power up the left one, then the battery console. It will not say "Lift Activated", but when you go into the chestburster room it will display. Return to the beginning of the level where you encountered the first warrior. You will see a lot of things. Shoot the facehuggers down with the pistol or flamethrower. You can pick up a flamethrower canister, pulse rifle, TAG, shotgun, and armor.

God mode:
Enter 1GOTP1NK8CIDBOOTSON as a password. All weapons, unlimited ammunition, invincibility, and access to every level will be available. A new option on the title screen will allow the display to be toggled between NTSC and PAL. Note that saving the game to a memory card will only save weapons and ammunition.