One Shot Kills
Put in the code Circle, L2, Down, R1, X
Put in the code Up, Square, Circle, X, Down
Put in the code X, Circle, Square, L2, R1
Put in the code L1, L2, X, R2, R1
Unlock All Acts
Put in the code R2, Right, L2, Up, Square
Unlimited First Aid Kits in Episode 2
In episode 2 when making the optical disc put in the Chris Barnes code first and do it over and over for med kits
Medical lab code
This code will get you into the medical lab in the hospital. go up to the door and hit x, then when the key pad shows put in:57383.
When playing as Mulder, after you exit the diner, when you are by the gas station, you will hear loud banging. DO NOT OPEN THE ICEBOX!! there is a zombie cat in there and it is VERY hard to kill.