Codes
takeonallcomers = Invincible
ifyouthinkyouarehardenough - All weapons and unlimited ammo
comeandhaveago - All weapons
nadiapopovXX - Level warp (where XX is 01-34)

Every weapon, unlimited ammo, invincibility
While playing, (there is no screen or box you need to bring up, the only thing you need is a keyboard) type in (must be all caps or else it doesn't work) RIPLEYDOESITWITHBIGGUNS You must hold down shift when you type the code or it won't work. I've tried it with all lower-case and It won't work. This is the mecha of all alien trilogy codes and is definitely kewl.