Doom 3 Cheats - Xbox

Skip Checkpoints
Hold [L] and press [B], [A], [X], [Y] during game play to advance to the next checkpoint. A sound will confirm correct code entry.

Invincibility
Hold [L] and press [X], [Y], [B], [A] during game play. A sound will confirm correct code entry. To verify that it is enabled, fire any weapon with splash damage at a nearby wall.

Cheat List for Ultimate Doom and Doom 2
These are the Ultimate Doom and Doom 2 cheats, which are only included with the Limited Edition Doom 3 game:

All Keys, Weapons and Ammo - Hold down [L] and press [A], [B], [A], [B].
Berserk Mode - Hold [L] and press [X], [X], [X], [Y].
End Level - Hold down [L] and press [A], [A], [B], [B].
Chainsaw - Hold down [L] and press [B], [B], [A], [A].
Weapons and Ammo - Hold down [L] and press [B], [B], [B], [B].
GOD Mode - Hold down [L] and press [A], [A], [A], [A].
Invisibility - Hold down [L] and press [X], [X], [Y], [Y].
Light Amplification Goggles - Hold down [L] and press [Y], [Y], [Y], [X].
Radiation Suit - Hold down [L] and press [X], [Y], [Y], [Y].
Show All Map - Hold down [L] and press [Y], [Y], [Y], [Y].
Temporary Invincibility - Hold down [L] and press [X], [X], [X], [X].

Nightmare mode
Complete the game once under any difficulty setting. When you start on Nightmare Mode. you will start with the Soul Cube.

Cabinet combinations
Cabinet 001: 396
Cabinet 003: 483
Cabinet 009: 752
Cabinet 013: 586
Cabinet 017: 347
Cabinet 023: 531
Cabinet 038: 409
Cabinet 039: 102
Cabinet 047: 123
Cabinet 048: 123
Cabinet 049: 123
Cabinet 054: 246
Cabinet 054 (second): 142
Cabinet 063: 972
Cabinet 064: 651
Cabinet 078: 364
Cabinet 079: 364
Cabinet 103: 259
Cabinet 104: 579
Cabinet 112: 538
Cabinet 114: 715
Cabinet 116: 972
Cabinet 116 (second): 624
Cabinet 117: 624
Cabinet 213: 371
Cabinet 215: 298
Cabinet 216: 624
Cabinet 217: 624
Cabinet 317: 841
Cabinet 386: 836
Cabinet 387: 836
Cabinet 452: 571
Cabinet 666: 372
Cabinet 669: 468
Martian Buddies 1 and 2: 0508
Weapons Storage 1 and 2: 584

Defeating the Guardian of The Soul Cube
When fighting the Guardian of The Soul Cube in hell, do not bother shooting his body. This is a waste of precious ammunition. Instead, blast his "searchers" with something with good coverage like the chaingun, and he will have to spawn more. When he does, a blue light will appear over his body. Shoot it with the rocket launcher. Do this a few times and he will die easily. Also, look in the room around the columns for ammunition, health, etc.

Defeating Sarge
Be prepared to die a few times. Beware of the edge of the room, as you can fall off. Also, do not hide behind the pillars for too long. They will open up and arc electricity periodically. When you walk into the room, a giant bay door at the opposite end of the room will open, revealing the "new and improved" Sarge. As soon as that door opens a crack, start lobbing rockets in there. After you score about six good hits without being splattered by his BFG, break out the Soul Cube (that you should have charged before entering the room) and let him have it. It should kill him and heal you. Pick up the armor and ammunition around the room before continuing.

Defeating Imps
If the Imp is jumping at you, blast it while it is in the air with the shotgun to kill it in one shot. This is slightly difficult to time.

As soon as an Imp has thrown a fireball at you, strafe around it with your shotgun equipped. Get very close to the front of the Imp and blast it in the chest. About 95% of the time, the Imp will die.

Defeating teleporting demons
When a demon teleports in (generally signaled by whisperings, a red tint throughout the screen, and always red lightning in the location where they will appear), you will have a split second before they are able to attack. Take a good weapon (for example, a shotgun or chainsaw for imps and wraiths) and stand close by. For powerful creatures, such as Pinkys, use a ranged weapon and stand at a safe distance. Remember to save the game often.

iD Software PDA
In the last level, just before you see the intermission sequence before the devil, instead of going to where the sequence begins the fight with the devil, go left. By the candles should be an ID Software symbol on the wall. Go towards the brick until you are touching it (you may have to duck). Press [Action] ([R]) when your crosshairs are over it. The brick will go inside the wall, and the wall behind you to the left will open. In that room will be a special PDA from iD Software, saying thanks for playing Doom 3 and other things. You can then fight the devil.

Saving ammunition
If you can avoid it, try not to use weapons like the shotgun or others that have difficult to find ammunition on the weaker zombies. The flashlight (if you are fast enough) or just the pistol usually will suffice.

Pumped up Soul Cube
After you acquire the Soul Cube, equip it and wait about one to two minutes. It will reveal its blades and spin for a very short time.

Bathroom scare
After you have found the lost scientist and are returning to the main building, find your way back to the bathrooms. Stand in front of the mirror with your pistol then cycle through until your shotgun then get very close.

Enpro Plant Sector 2 plasma room door code
The door code for the plasma room in Enpro Plant Sector 2 is 734. Be careful; leaving that room causes several creatures to transport directly outside the door, but it is worth it.

Classic Doom reference
When you get to Mars City, go to the kitchen. Look closely at the video game in the back to see a classic Doom screen while you punch the turkey. Also, in the last few levels are stone tablets that feature the original Doom cover.

Super Turkey Puncher Three
Go to the first level in Co-Op mode and proceed through the level until 'Command Access Junction'. There you can find two Super Turkey Puncher arcade machines made by 'Nabcon'. On the screen is the face of the original Doom Guy and also makes the same faces when you punch the turkeys. First player to 3000 points wins.