Skip checkpoints While playing the game, hold L and press B, A, X, Y to advance to the next checkpoint. If you entered the code correctly, you will hear a sound.
Invincibility
While playing the game, hold L and press X, Y, B, A. If you entered the code correctly, you will hear a sound. Note: The code cannot be enabled until you take the elevator after being attacked at the start of the game. When a new area is loaded, the code must be re-enabled to regain its effect.
Level skip in Doom 2 and Ultimate Doom
While playing the game, hold L and press A(2), B(2). If you entered the code correctly, you will hear a sound.
Toggle God and Degreelessness mode in Doom 2 and Ultimate Doom
While playing the game, hold L and press A(4). If you entered the code correctly, you will hear a sound.
All weapons, health, keys, and armor in Doom 2 and Ultimate Doom
While playing the game, hold L and press B(4). If you entered the code correctly, you will hear a sound.
Temporary invincibility in Doom 2 and Ultimate Doom
While playing the game, hold L and press X(4). If you entered the code correctly, you will hear a sound.
Toggle invisibility in Doom 2 and Ultimate Doom
While playing the game, hold L and press X(2), Y(2). If you entered the code correctly, you will hear a sound.
Toggle Berserk mode in Doom 2 and Ultimate Doom
While playing the game, hold L and press X(3), Y. If you entered the code correctly, you will hear a sound.
Full map in Doom 2 and Ultimate Doom
While playing the game, hold L and press Y(4). If you entered the code correctly, you will hear a sound.
Chainsaw in Doom 2 and Ultimate Doom
While playing the game, hold L and press B(2), A(2). If you entered the code correctly, you will hear a sound.
Radiation suit in Doom 2 and Ultimate Doom
While playing the game, hold L and press X, Y(3). If you entered the code correctly, you will hear a sound.
Light amplification goggles in Doom 2 and Ultimate Doom
While playing the game, hold L and press Y(3), X. If you entered the code correctly, you will hear a sound.
Nightmare mode
Successfully complete the game on any difficulty setting to unlock the Nightmare difficulty setting. When you start in Nightmare mode, you will start with the Soul Cube.
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.
Save scientist
In Delta Labs Level 3 South, almost as soon as you enter a room, you will see a zombie marine shooting a scientist. It is possible to save him using the Soul Cube in Nightmare mode. Make sure you have the Soul Cube charged. As soon as you enter the room, use the Soul Cube on the marine. The scientist will be unharmed and run away. You must be very quick when you do, and it may require a few attempts.
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.
BFG
At Chief M. Abram's office, the BFG is in the test chamber when you are there to retrieve the plasma inducer. You will see the BFG in a test chamber in a room that is locked. Enter 931 as the code to get the BFG.
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.
Disappearing person
Play a co-op game on Xbox Live. In the room with about two or three pretty big Pinkeys (they walk on all fours), there should be a person lying against the wall. On one screen, it should be there. On the other screen, it is not.
Defeating the final Boss
When you each the end Boss, do not bother wasting your ammunition on him. Just stay away from him. Kill the Imps and other demons and use the Soul Cube on him. If you are play in co-op mode, shoot him. Use the Soul Cube on him about five or six times. On the last time you will see an intermission sequence of him dying.
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 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. Additionally, 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. Also, when Imps shoot their energy ball at you, crouch underneath it and run at them. Then, pump them in the face with the shotgun.
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. Additionally, use the following trick to kill the new and improved Sarge much easier. The key is to use the chaingun. It will blow up his BFG bullets in his face. It will take about thirty seconds to kill him in this way, and you do not have to use the Soul Cube. There is is a video disc that you will get just before you fight him that explains the BFG, and says that small arms fire will blow up the chip in the ball of energy, making it explode instantly.
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.
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.
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. Additionally, in the last few levels are stone tablets that feature the original Doom cover.
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.
