Doom 3

Doom 3 is a retelling of the original Doom, but using a completely new engine with true 3D and advanced physics. Doom 3 is not as "run and gun" as its predecessors, but focuses on atmosphere and graphics. It was criticized mainly for using clichéd horror effects, and the underuse of it's physics engine. It is only available for the X-Box and PC.

Plot
The protagonist is once again a nameless space marine. As it just so happens, he gets shipped to the UAC Mars research facility with Counselor Swann and his bodyguard Campbell on the same day all Hell breaks loose. Within minutes of the invasion, the main military units are destroyed or zombified. It is once again upon the player to stop the forces of Hell from reaching Earth.

The first cutscene displays Swann saying how fed up he is to Campbell about being sent to Mars to check security. Swann says to Campbell he is "...tired of doing damage control every time [he] screws up." Swann is later seen arguing with the head research scientist in Delta Labs, Dr. Malcom Betruger, saying there are to many incidents happening throughout the base, along with frightened employees and rumors of what is happening in Delta Labs.

The player's first mission, assigned to him by Master Sergeant "Sarge" Kelly, is to find a missing scientist that was said to be seen at the old communications facility. When you find him, he is babbling about warning the fleet about teleporter experiments. "The Devil is real. I know. I built his cage." With those words, Hell erupts from the gateways, sending a shockwave through the complex, along with glowing pentagrams and a typical evil villain laugh.

Gameplay
Doom 3's gameplay was as fast paced as the games before it. Most of the game is extremely dark, and there is no Light amplification visor. Instead the player must rely on a flashlight that can only be used in place of a weapon. There are few tactics involved other than grabbing the biggest weapons.

Much of the game takes place in dark close-quarters with demons ambushing from every direction. By contrast the Hell section of the game is considered by many to be the best, as it features more open areas and makes use of unique effects.

Weapons

 * Fists: A short range melee weapon. Fists have a slow repeat-rate and are weak; do not use unless you have the Berserker power-up. In Deathmatch, fists can be used to steal a weapon out of an opponent's hands.


 * Flashlight: Used mostly to light up areas to see your way around, it can also be used as a blunt instrument. It has slightly longer range than the fists when used in this way. Do not use on anything stronger than an Imp. In deathmatch, using the flashlight alerts other people to your whereabouts. Not included in Xbox Deathmatch.


 * Chainsaw: Another melee weapon that deals out damage fast and stalls the enemy. You can have some fun cutting up everything if you have enough health and armor. Even more fun when you have the berserker power-up. Not available in PC Deathmatch. In Xbox DM it replaces the plasma gun.


 * Pistol: A semi-automatic weapon that is extremely weak but also very accurate. Headshots are more effective than body shots.
 * Clip size: 12 bullets
 * Reloading: Fast
 * Ammo: Bullets


 * Shotgun: Devastating up close but not as powerful at long distances or accurate. Slow rate of fire. You can reload two shells at a time.
 * Clip size: 8 shells
 * Reloading: Slow
 * Ammo: Shells


 * Machine gun: The MG-88 Enforcer has a big clip size, high rate of fire, and great accuracy. Useful against most demons up to the Cacodemon.
 * Clip size: 60 bullets
 * Reloading: Normal
 * Ammo: Clips


 * Chain gun: Very powerful; good belt size; extreme accuracy; heavy recoil; slow warm-up time. This should be used for Cacodemons, Revenants, Mancubi, and Hell Knights.
 * Clip Size: 60 bullets
 * Reloading: Fast
 * Ammo: Ammo Belt


 * Plasma Gun: The Plasma Gun has been toned down. It can sustain a high rate of fire, can hold plenty of rounds in a cell but the projectiles move more slowly than the classic equivalent. It still deals good damage and is good for taking out mid-air rockets. Not in Xbox Deathmatch.
 * Clip size: 50 cells
 * Reloading: Fast
 * Ammo: Cells


 * Rocket launcher: Carries high explosive rockets, semi-automatic fire, and fast reloading. In multiplayer can be used for rocket jumping.
 * Clip size: 5 rockets
 * Reloading: Fast
 * Ammo: Rockets


 * BFG 9000: The ultimate gun. Based on Quake II's BFG 10000 version, the BFG shoots a slow moving ball of plasma that contains a small computer chip. This chip shoots lasers at opponents before the initial explosion that will kill most demons near the blast.
 * Clip Size: 4 BFG cells
 * Reloading: Slow
 * Ammo: BFG Cells

References to Classic Doom
Main article: References to Classic Doom in Doom 3.

Final Storyline
In a later cutscene, Swann is seen in a video phone conference with Betruger who is rather calm about the situation. It seems Betruger wanted all this to happen. After deciding on whether to alert the orbital fleet, Betruger addresses you over a computer screen and says that once the fleet arrives, his legion will take the ships back to Earth.

Later in the game, the player runs into a colleague of Betruger, who says that he became obsessed with the teleporters when he figured out Hell existed on the other side. He says he took an artifact called the Soul Cube from the archaeological digs from the ancient Martian civilization into Hell, and demons followed him out.

The player never meets up with the remaining Marines, and only sees Swann and Campbell on their deathbeds. Swann was badly injured, and Campbell went on to hunt Sarge. Swann says that Kelly betrayed his men and is now on Betruger's side. After killing Sarge, the player find an archaeologist, who explains that the Soul Cube must be used to kill the Cyberdemon.

After defeating the Cyberdemon, the game ends, leaving many details unanswered.