Doom Cheats

You can find this area in the Toxic Refinery (Episode 1, Level 3). Complete the first half of the level (before you enter the blue door), then go back to the starting point. Look inside the pool of radioactive waste and you should see a platform (if you flipped all the switches in the first half). Walk across the platform towards the wall it leads to. The wall will open and you will have to defeat a series of enemies. Explore the secret area more and you should find an exit door. Enter it and flip the switch (the stats will not appear). You will now be an area called the Military Base. Note: This area can be very difficult.

Invincibility: A,A,B,A,A,A,A,A (Do NOT type to fast.. duh,.duh.,duh,.duh,. like that)
All ammo,secret Items and all guns:A,B,B,A,A,A,A,A
O yes while typing in codes, hold l1 and r1 :)

Press L & R in Pause Menu, then press he following buttons to activate the cheats

All Weapons, items and Keys:
A,B,B,A,A,A,A,A

Berzerk Mode:
B,A,B,A,A,A,A,A

Skip to Level, Tower of Babel:
A,B,A,B,A,B,B,A

Computer Map:
B,A,A,A,A,A,A,A

Pause the game, then hold L + R and press
B, A, B, A, A, A, A, A.