Doom 3

Doom 3 is a sci-fi horror first-person shooter computer game developed by id Software and published by Activision.

Set on November 15 and 16, 2145 on Mars, Doom 3 is a horror-focused game unlike previous action-packed entries.

Doom 3 had a long development schedule dating back to 2000, with a well-received demonstration at E3 in 2002, 2003 and 2004. The game was finally released in August of 2004.

The game was developed for Windows and ported to Linux in 2004; five months later, it was also released for Mac OS X (ported by Aspyr) and Xbox (co-developed by Vicarious Visions). The Xbox version is graphically similar to (although less detailed than) the original and features an additional two-player online co-operation mode. An expansion, Doom 3: Resurrection of Evil, developed by Nerve Software and co-developed by id Software, was released on April 4, 2005, and released several months later for Xbox as well. A Doom movie, loosely based on the franchise, was released roughly six months later on October 21, 2005.

Doom 3 focuses on slow methodical gameplay, as opposed to the "run and gun" feel as its predecessors. It received a positive reception for its fear-inspiring atmosphere and groundbreaking graphics, but was criticized mainly for its otherwise simplistic gameplay and clichéd horror effects.

The source code for Doom 3 was released under the GPL.

Features
According to John Carmack, the lead graphics engine developer of id Software, the "tripod of features" in Doom 3 technology-wise is:
 * Unified lighting and shadowing
 * Complex animations and scripting that show off real-time, fully dynamic per-pixel lighting and stencil shadowing.
 * GUI surfaces that add extra interactivity to the game

The key advance of the Doom 3 graphics engine is the unified lighting and shadowing. All 3D engines up to and including Quake III and Unreal Tournament had computed or rendered lightmaps during map creation, saving that information in the map data, which made the lighting extremely static. By contrast in the new Doom 3 engine, most light sources are computed on the fly. This allows lights to cast shadows even on non-static objects such as monsters or machinery, which was impossible with static lightmaps. A shortcoming of this approach is the engine's inability to render soft shadows and global illumination.

As well as dynamic lighting and shadows, the Doom 3 engine was id Software's first to make extensive use of bump mapping.

To create a more movie-like atmosphere, id interspersed the gameplay with many in-game animated sequences of monsters ambushing the player or just lurking around.

To increase the interactivity with the game-world, id designed hundreds of high-resolution animated screens for in-game computers. Rather than using a simple "use key", the crosshair acts as a mouse cursor over the screens allowing the player to use a computer in the game world. This allowed an in-game computer terminal to perform more than one function, such as a readily apparent door-unlocking button, combined with a more obscure function allowing an astute player to unlock a nearby weapons locker.

Other important features of Doom 3 engine are normal mapping and specular highlighting of textures, realistic handling of object physics, dynamic, ambient soundtrack and multi-channel sound.

Hardware requirements
A disadvantage of id Tech 4 was that it needed a high-end graphics processing unit (GPU), which was at least DirectX 8.0 compliant with fully programmable vertex and pixel shaders, such as the Nvidia GeForce 3 or ATI Radeon 8500, with 64 MB of VRAM. By E3 2002, the recommended GPU was the Radeon 9700; while its DirectX 9.0 features are not necessary to render the game, its advanced architecture, 256-bit memory bus, and efficiency were needed to run Doom 3 at high detail and playable speed.

id Tech 4 resulted in the obsolescence of DirectX 7.0 graphics chips such as the widespread GeForce 2 and Radeon 7200, as well as DirectX 6.0 chipsets such as RIVA TNT2 and Rage 128, and software rendering (with an integrated Intel GMA). Owners of pre-DirectX 8.0 cards were able to use a powerful CPU to compensate for the lack of hardware Transform, clipping, and lighting (T&L) in DirectX 7.0 titles, however DirectX 8.0 calculations were far too complex for a DirectX 7.0 card or a fast CPU. While John Carmack initially warned gamers not to purchase the GeForce 4 MX (which was an improved GeForce 2), its somewhat widespread adoption compelled id Software to enable Doom 3 to run on these cards, making it the only DirectX 7.0 chip capable of running Doom 3. Some have gotten Doom 3 to run on unsupported cards such as a 3dfx Voodoo2, however this video chipset was incapable of rendering anything beyond the polygons and textures, such as the per-pixel lighting and bump mapping.

id Software pointed out that the original Doom and Doom II had gamers moving from their 386s to 486s, while the first Quake had them switching to Pentium processors. They hope that Doom 3 would do the same in getting the masses to adopt DirectX 8.0 hardware. However, from 2001-2003, DirectX 8.0 capable video cards were extremely expensive, never spawning a mass market version like their DirectX 7.0 predecessors, putting them out of the range of all but the most hardcore gamers. For instance, the GeForce 3 and GeForce 4 Ti lines never spawned mainstream versions, while the Radeon 8500's mass-market derivative in the Radeon 9000 did not have the best performance.

Development
In June 2000, John Carmack announced the start to a remake of Doom using next generation technology. This plan revealed controversy had been brewing within id over the decision.

Kevin Cloud and Adrian Carmack, two of id Software's owners, were always strongly opposed to remaking Doom. They thought that id was going back to the same old formulas and properties too often. However, after the warm reception of Return to Castle Wolfenstein (which was originally a remake of Wolfenstein 3D) and the latest improvements in rendering technology, most of the employees agreed that a remake was the right idea and confronted Kevin and Adrian with an ultimatum: "Allow us to remake Doom or fire us" (including John Carmack). After the reasonably painless confrontation (although artist Paul Steed, one of the instigators, was fired in retaliation), the agreement to work on Doom 3 was made.

The game was in development for 4 years. In 2001, it was first shown to the public at Macworld Conference & Expo in Tokyo during the unveiling of Nvidia's GeForce 3, with Apple CEO Steve Jobs introducing John Carmack on stage, who showed off a few new screenshots of id Tech 4, including some from Doom 3.

It was later demonstrated at E3 in 2002 using an ATI Radeon 9700, where a 15-minute gameplay demo was shown in a small theater. It won awards at E3 that year. It starts off an early version of Dr. Betruger (with spectacles) pushing his way past a couple security guard to initiate a test run. However, computer systems started going haywire and evil spirits were released from a portal. One guard is possessed by the spirit and briefly lifted into the air, with his skin shriveling up and his goggles/visor exploding as he is transformed into a mindless zombie. After a brief vision of hell, the movie cuts to a nameless marine, taking the player's first-person shooter view. The player kills various zombies, commandos, imps, and pinky demons, before running out of ammo and being killed by a Hell Knight, who then rips off the player's head (the camera view) and eats it. One memorable scene is when a Pinky Demon is eating the intestines of a Fat Zombie in the bathroom.

At the same time of the E3 2002 demo showing, a downloadable film made by Fountainhead Entertainment was released, called Doom III: The Legacy, which contrasted Doom/Doom II with the new Doom 3 and featured interviews with key id Software staff.

Some speculated that id Software was targeting the 2002 holiday season, although others believed a 2003 release date would be more realistic. After E3 2002, there was no further press release from id Software regarding the project; the company's website only had Return to Castle Wolfenstein as the latest game.

Next year, a new trailer was shown at E3 2003 and soon afterwards the id software homepage was updated to showcase Doom 3 as an upcoming project but it was also announced that Doom 3 would not be ready for the 2003 holiday season. According to some comments by John Carmack, the development took longer than expected. Originally, the game was planned for release around the same time as another highly anticipated game, Half-Life 2, in Christmas 2003. Doom 3, Half-Life 2, and Halo 2 were considered among the most anticipated games since their announcements in 2001/2002, though all three of them would not make the planned 2003 holiday season.

Doom 3 achieved gold status on July 14, 2004, and a Mac OS X release was confirmed the next day on July 15, 2004. Doom 3 was released in the U.S. on August 3, 2004. Additionally, a Linux version was released on October 4, 2004. Due to high demand, the game was made available at select outlets at midnight on the date of release. The game was released to the rest of the world on August 13, 2004 (except for Russia and other countries of the former Soviet Union, where official localization was delayed and caused the game to be released about four months later, on December 10, 2004).

Plot
As Earth's largest corporate entity with unlimited fundings, the Union Aerospace Corporation engages in research outside of legal and moral activities. Originally focused on weapon and defense contracts, the UAC eventually ventures on further fields such as biological research, space exploration, and other scientific endeavors.

The UAC's very first project involves on terraforming Mars with the creation of the Hydrocon. During the initial construction of Mars City, UAC engineers discovered underground ruins and structures of what used to be an ancient Martian civilization that existed millennia prior. Thus, the UAC shifted their project on Mars to function as an Archeological Excavation Site, with labs and general posts established in different locations. By 2104, one of the archaeological teams discovered a series of artifacts in the caverns, later named Site 3. This area consisted of stone tablets written by the ancient Martian civilization, and a mysterious cube-shaped artifact, they would later call as the Soul Cube.

Within the stone tablets contained written knowledge and technical information on a powerful teleportation technology. The UAC then shifted their primary focus on recreating this lost technology they discovered in a secured location known as the Delta Labs, supervised by their top head scientist and Hydrocon creator Dr. Malcolm Betruger. At the same time, lead archaeologist Dr. Pierce Rogers's team continued on with UAC's original project in Site 3 by further translating the glyphs contained in the tablets. Dr. Rogers later discovered the glyphs reveal a warning of a grave threat on this teleportation technology, which wiped out the once powerful Martian civilization until it was contained by the Soul Cube.

Meanwhile, Dr. Betruger discovered that this teleportation technology wasn't exactly teleportation, but rather a portal device that led to another dimension. After several tests with cameras and animal subjects, the scientists discovered that this dimension was filled with sweltering heat and hideous creatures. Further curious, Betruger attempted to use human subjects. However, many test subjects never returned from their expedition, while those who returned later succumbed from immense psychological trauma. A growing number of Delta Labs scientists later voiced their concerns, with some of them such as Ian McCormick and Jonathan Ishii theorizing that this dimension they discovered was Hell.

In spite of these tragic events, Betruger, becoming obsessed with the other dimension, continues on with the teleportation project, further exploring and exploiting the other dimension's discoveries, such as bringing back dead and live specimens. Following Betruger's continuation with this project, the whole Martian base eventually went through a strange outbreak of fatal accidents, psychological problems, and supernatural occurrences. The experiments led Betruger to become corrupted by the power and authority he held, using it to control Mars City and hide the horrors of his discoveries from Earth. On one occasion, he entered into the portal himself, taking the Soul Cube with him, only to return and be seen as a different person by the rest of the staff.

In response to the increasing worries about the Delta Labs experiments and the chain of accidents and complaints from UAC employees, Dr. Elizabeth McNeil called on the UAC Board to terminate Betruger's Delta Labs project. This unfortunately led to her expulsion off Mars by Betruger. However, the UAC Board of Directors on Earth, acknowledging McNeil's concerns, later appointed the company's lawyer and councilor Elliot Swann and his bodyguard Jack Campbell to assess the situation in Mars by enacting "damage control".

On the date of Monday November 15, 2145, the Phantom Dropship Darkstar arrives at Mars City. The passengers who exit the ship consist of Swann, Campbell, and the protagonist, who is an unnamed Marine holding the rank of a Corporal. This Marine was transferred in as a replacement for another Corporal who was sent back to Earth for psyche problems. He is immediately instructed by Master Sergeant Kelly, a.k.a "Sarge", to report directly to Marine HQ upon arrival.

Meanwhile, Councilor Swann and Campbell engages in a heated discussion with Betruger about the chain of incidents that have been plaguing Mars as of late. Betruger, not wanting to waste any more words with Swann states that "amazing things will happen here soon," before leaving.

Once the Marine reports himself to Sarge at HQ, he is given his first mission to locate a missing scientist name Dr. Jonathan Ishii. After being properly geared and ready for combat, the Marine then makes his way to locate Ishii, who was last seen in the Old Communications Facility. Ishii is later discovered to be sending a direct warning to Earth about Betruger's Delta Labs experiment. Before that can be done however, the main portal in the Delta Labs suddenly undergoes a containment breech, causing countless waves of demonic spirits from Hell to pour out; the invasion begins.

Demonic forces suddenly rip their way throughout the base, killing a majority of the human population on Mars and possessing many more into hostile Zombies, including Ishii. Forced to deal with this new threat, the Marine gets his next orders from Kelly to fall back to Marine HQ to wait for further orders.

As the Marine proceeds to battle through the now zombie and demon-infested hallways, he eventually makes it back to Marine HQ to discover that he's the only soldier alive. Setting up communications with Kelly, he is given his next mission, to link up with the last active Marine squad, Bravo Team and get a distress call sent to Earth for reinforcements. Kelly then pinpoints the Marine to the Alpha Labs as the quickest way to find them.

Meanwhile, at the Administration Complex, Swann continues on with his argument with Betruger through a telecam call in regards to the current crisis that is happening. Realizing that Betruger is not willing to cooperate to his own demands, Swann then asks Campbell to initiate "Plan B", which is later revealed to exterminate all of Mars's communication relays from Earth, while Campbell helps fend off any demons so he can safely escort Swann.

The Marine continues to make his way throughout the Alpha Labs to quickly link up with Bravo Team, continuously battling through zombies and demons that get in his way while having Kelly to continue monitoring his progress on how close he is. However, by the time Bravo Team reaches the EnPro Facility, they get wiped out in an ambush set up by a large horde of Imps and Wraiths. Kelly reports to Marine about Bravo Team's current status, and thus gives him his next mission, to retrieve a transmission card from them in order to send a distress signal to Earth's fleet for reinforcements.

Swann and Campbell are briefly seen locating the transmission card themselves in order to confiscate it, only for them to give up before moving to the Communications Facility.

The Marine arrives to where Bravo Team last was. One mortally-wounded survivor of the squad approaches the Marine and gives him the card, before being killed by a Wraith. Kelly then instructs the Marine to head to the Communication Facility to set up a distress signal, while being wary of Swann and Campbell, who are attempting to hinder the Marine's progress of calling for reinforcements.

When the Marine finally reaches Communications, Campbell sabotaged the main communication console with his BFG 9000, rendering it useless. Sarge orders the Marine to head towards the isolated satellite tower, the only communication relay left intact. As the Marine prepares to send the transmission, Swann suddenly contacts him through a video call, urging him not to, instead preferring to keep the invasion quarantined in Mars until they can keep it contained. The Marine makes his decision on whether to follow Sarge's or Swann's request.

After sending/canceling the transmission, the Marine is ordered by Sarge/Swann to go to Delta Labs and help stop the invasion. Granting security clearance to the Monorail that leads a direct path to the Delta Labs, the Marine becomes intercepted by Betruger who forces him to take the long way through the Waste Recycling Center. There, Betruger reveals himself as the main culprit of starting the invasion. Depending on the Marine's prior choice of sending/canceling the transmission, Betruger will mockingly thank the Marine for playing his cards or attempt to alert the fleet himself, as he then announces his plans to have the demons overrun the Earth's fleet to spread this invasion back to Earth. Ensuring the Marine's death before he can be stopped, Betruger then floods the entire Recycling Center with toxic gases in an unsuccessful attempt to kill him.

After passing by the Recycling Center and the Monorail, the Marine finally makes his way to the Delta Labs. However, neither Kelly nor Swann is present. Instead, the Marine is left a recorded video message from Kelly to meet him at a nearby location in the Delta Labs. As the Marine proceeds his way there, he encounters Ian McCormick, one of the Delta Labs scientists who was involved in assisting Betruger's teleportation experiments. Providing further background about the invasion, McCormick explains to the Marine that the only way to stop this invasion is to retrieve the Soul Cube back from Hell, which Dr. Betruger took through the main portal in Sector 4, moments before the invasion begun. To get to the main portal, McCormick asks the Marine to assist him on getting the teleporters in the entire Delta Labs operational again.

After restoring the teleporters back online, the Marine then proceeds throughout the Delta Labs, while Betruger continuously summons his demons to impede the Marine's progress, mocking him that his journey is futile. Finally, the Marine makes his way to Delta Labs - Level 4, the site of the main teleporter where the invasion ultimately started. Upon arriving to the main teleporter, Betruger activates it, sending two Hell Knights to stop him. After the Marine kills them both, Betruger reactivates the portal, sending the Marine directly to Hell.

Completely stripped of his weapons, the Marine is forced to acquire whatever supplies he can find as he proceeds through the fiery depths of Hell, fighting against many of its ghastly inhabitants until he can locate the Soul Cube. Imprisoned by a giant demon, known as the Guardian of Hell, the sentient cube verbally assists the Marine by exploiting the Guardian's weakness. After defeating the giant demon, the Soul Cube speaks to the Marine, acknowledging him as its master and promises to fight alongside him as the Cube is "the only way to destroy Hell's Mightiest Warrior".

Upon arriving back to Mars with only the Soul Cube in his hands, the Marine seals the main portal to the Delta Labs. But not long after, Betruger further mocks the Marine by stating he already opened another Hell Hole in the Caverns. With Earth's fleet arriving soon, Betruger remains confident that his plans to spread the invasion to Earth will succeed.

After traversing through a few areas in the Delta Complex, the Marine finds a badly injured Swann, who is surprised to see him still alive. Swann then explains that Sarge has converted to the demon's side, leaving Campbell to go after him. He also expresses fear that with Hell breaking through the Caverns, Earth will be doomed if the Fleet arrives any sooner. Swann then entrusts the Marine by providing his PDA, hoping he can completely subdue the invasion and hunt down Sarge. Meanwhile, Campbell continues his hunt for Sarge in the CPU Complex, not long before being mortally wounded and having his weapon looted by him. The Marine eventually discovers Campbell's fate, who shortly succumbs to his wounds. Sarge then taunts the Marine that he will come for him next. The Marine proceeds through the CPU Banks to locate Sarge, only to find him transformed into the demonic Sabaoth. Having no other choice but to fight his former commander officer, the Marine defeats him, putting Sarge out of his misery.

With Sarge dead, the Marine is left with one final task, to go to the Caverns and seal the remaining Hell Hole. Making his way towards Site 3, he discovers a lead archeologist named Dr. Pierce Rogers. Knowing that the Soul Cube is the only way to stop the invasion, he becomes surprised and relieved to see the Soul Cube in the Marine's hands. Dr. Rogers then provides his own PDA to the Marine and urges him to head into the Caverns quickly.

As the Marine enters the original Mars Base (Caverns 1), it's already Tuesday November 16th and he reaches the Caverns at dawn. After engaging several demonic forces with the help of the Soul Cube, the Marine finally reaches the Primary Dig Site (Site 3), the main location of the only remaining Hell Hole. Going deep down within the bowels of an underground Martian chamber, he also discovers a section of Hell that has completely consumed the chamber. Progressing further on, the Marine encounters the largest and most powerful demon of Hell, the Cyberdemon, guarding the Hell Hole. Standing right next to Marine, the towering monster unleashes a mighty roar at him, before proceeding to challenge him. After a lengthy epic fight, the Marine uses the Soul Cube to deliver a finishing blow on the Cyberdemon, killing it instantly. The Cube then enters through the Hell Hole, completely destroying Hell's only link to the human dimension.

Few days later, on November 20, 2145 at 9:36pm, the Marine team, Recon Zulu, and their Sentry Drones arrive on Mars City to secure the base. They discover the Marine in the Delta Labs as the lone survivor, taking him into medevac. Recon Zulu was able to locate Councilor Swann who unfortunately lies dead, succumbed from his wounds. However, they were unable to locate Dr. Betruger.

The game ends in Hell, revealing that Betruger has now become the dragon-like demon known as the Maledict.

Changes from original Doom
For Doom 3, id Software employed a professional science-fiction writer named Matthew J. Costello to write the script and assist in storyboarding the entire game. id Software focused on retelling the story and creating a tense horror atmosphere instead of the brisk, action-packed atmosphere of the original games. The game's events and atmosphere show a great deal of influence from George Romero's Living Dead, series and James Cameron's Aliens, as well as Valve Software's Half-Life.

The plot itself is similar to the UAC Mars Base invasion mentioned in the Doom II manual.

Also similar to the story of the original Doom, this entry focuses on the marine who is transferred to Mars after striking an officer on Earth and sent out on a routine mission, and who needs to kill zombies and demons from Hell. One difference is that Doom 3 is set on Mars itself, whereas the first two episodes of the original Doom take place on Phobos and Deimos, respectively (Mars is always considered secured by the humans).

The environment of Doom 3 is generally much more realistic. For example, whereas the original Doom gives the two moons breathable atmospheres, Doom 3's Martian atmosphere is unbreathable (although oxygen tanks allow the player to breathe for a brief time), but the gravity is still the same as Earths, instead of being slightly lower like Mars should be. (If the player with all his gear weighed 300 pounds on Earth, he would weigh 120 pounds on Mars.)

In both cases, the protagonist visits Hell. In the original Doom, it is the third episode, Inferno (The Ultimate Doom adds a fourth, Thy Flesh Consumed, which takes place back on Earth), whereas in Doom 3, it is only one level (the Xbox version's Hell level is separated into three levels, to make it easier on the console). However, Doom 3's Hell level is much longer and more intense than the others, with the screaming of damned souls and steaming pools of hot magma. It also has a boss called the Guardian. Other bosses include a tank-like cyborg called Sabaoth and the final boss, the Cyberdemon.

Unlike in previous id games, there are now cutscenes that give purpose and context for the player's actions and introduction to new enemies. Similar to other science fiction action/horror games such as ', ', and , hundreds of text, voice, and video messages are scattered throughout the base. The messages are internal e-mails and audio reports sent between doctors, scientists/lab workers, administrators, maintenance staff, or security personnel at the Mars base. The messages explain the background story, show the feelings or concern of the people on the Mars base, and reveal information related to plot and gameplay. Video booths and televisions give planetary news, corporate propaganda, visitor information, or technical data about the base and even weapons.

The story of Doom 3 surrounds the discovery of ancient ruins underneath Martian soil. Tablets found at these sites record how an ancient Martian race developed a form of teleporter technology. They realized an important fact all too late, as the route the teleporter took passed through Hell itself. Quickly invaded by demons, this alien race created and sacrificed themselves to a weapon known as the Soul Cube. This cube, powered by the souls of almost every being of this alien race, was used by their strongest warrior to defeat the demons and contain them in Hell.

Having done so, the remainder of the alien race constructed warnings to any who visited Mars, warning them not to recreate this technology; to avoid opening another gate to Hell. They then teleported to an unknown location, fleeing Mars; there are hints that at least some of them fled to Earth, and that humans descended from them. It's stated that the demons once inhabited Earth in an unknown context, but lost possession of it due to an unknown cause. Consequently, the demons want to reclaim Earth.

Gameplay
Doom 3's gameplay was not as fast-paced as the games before it. Some areas of the game are very dark, and there is no Light amplification visor, nor do weapons have a flashlight attachment. 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 level of the game is considered by many to be the best, as it's more similar to the Doom games of the past, featuring more open areas and making use of unique effects.

Difficulty
There are four difficulty levels in Doom 3: Recruit, Marine, Veteran, and Nightmare. The first three are always available. On Recruit difficulty, there are fewer monsters, but it is a negligible amount. The principal difference between the difficulties is the amount of damage the player receives. The chart on the right indicates the amount of damage the player will receive on each difficulty level, relative to the definition files (.def).

Upon completion of a campaign regardless of difficulty level, the player unlocks the "Nightmare" difficulty setting. When playing the game on this setting, the player's health falls in 5-point increments at 5-second intervals until it reaches 25, where it remains steady. Additionally, there are absolutely no medkits throughout the game; the only means of procuring health is either by the health stations, which are still operational, or use of the Soul Cube, which is given to the player at the very start of the game.

The difficulty setting can be controlled by the controllable variable,. The damage changes take effect immediately, but a map restart or change is necessary for the rest. For example, if a player begins the level on Recruit difficulty and then enters  in the console, immediately their health will begin its drop to 25 and they will receive Nightmare damage. However, the Soul Cube is not given, medkits remain in the level, and the amount of monsters does not increase.

Weapons
Most of Doom 3's weapons are updated versions of the classic weapons, but those marked with an asterisk are new additions to the series. Several weapons are also based upon these found in Quake II.

As the game generally takes place in dark mazes, there is no long distance "sniper" weapon such as the Railgun found in Quake II and Quake III; this omission was notable as it was a FAQ.

Unique to Doom 3 is its reloading mechanic. Every firearm has a set amount of ammo players can repeatedly fire before they have to momentarily pause to enter reloading animation. Players are therefore expected to manually reload every now and then to manage their inventory more efficiently, as reloading during the midst of combat will make them vulnerable.

Ammo pools as seen in earlier Doom games do not exist. The pistol, machine gun, and chaingun each have their own respective caliber instead of sharing the same class of ammunition. This is also the case with the Plasma Gun and the BFG.

Players can also utilize sentry bots that will aid them as "gun buddies" in some areas. Certain items and contraptions (such as machinery and barrels) in the area can also be exploited, manipulated, or avoided at will.


 * Fists
 * Flashlight*
 * Pistol
 * Shotgun
 * Machine gun*
 * Chaingun
 * Plasma gun
 * Rocket launcher
 * Super Shotgun
 * BFG 9000
 * Chainsaw
 * Grenades*
 * Soul Cube*

Enemies
Doom 3 includes updated versions of many monsters from the original games, and also introduces some new ones. Some of the old monsters such as the Revenant and Mancubus are fairly reminiscent from their original versions, while others, like the Commando and the Pinky, are a lot different in terms of appearance and behavior.

The enemies are divided into two groups: zombies and demons. Zombies are former humans possessed by Hellish spirits that are now hostile to the player, while the demons are the creatures from Hell.

Like the classic games, the player is expected to fight bosses, which are the more powerful enemies than the more frequently encountered ones. Defeating them will grant the player either an item or further access to the level.

Unlike classic Doom, the enemy bodies instantly dissolve upon death, except forever Zombies and certain bosses. In addition, gibbing, which was a feature in the classic games, can only be done to Zombies and human corpses, in which the case the remains will gradually disappear like most enemies.


 * Arch-vile
 * Cacodemon
 * Commando
 * Cyberdemon
 * Hell Knight
 * Imp
 * Lost Soul
 * Mancubus
 * Pinky
 * Revenant
 * Zombie
 * Chainsaw Zombie
 * Fat Zombie
 * Flaming Zombie
 * Morgue Zombie
 * Z-Sec

Additionally, the following new monsters are encountered:


 * Cherub
 * Guardian
 * Seeker
 * Maggot
 * Sabaoth
 * Tick
 * Trite
 * Vagary
 * Wraith

Several monsters were also left unfinished and were not included in the finished game.

Levels

 * 1) Mars City
 * 2) Mars City Underground: Union Aerospace Subsystems
 * 3) Mars City: Union Aerospace Corporate Division
 * 4) Administration: Union Aerospace Corporate Division
 * 5) Alpha Labs - Sector 1: Union Aerospace Science Division
 * 6) Alpha Labs - Sector 2: Union Aerospace Science Division
 * 7) Alpha Labs - Sector 3: Union Aerospace Science Division
 * 8) Alpha Labs - Sector 4: Union Aerospace Science Division
 * 9) Enpro Plant: Energy Processing and Storage
 * 10) Communications Transfer: Maintenance and Transfer Station
 * 11) Communications: Central Communications Tower
 * 12) Monorail Skybridge: Facility Transport
 * 13) Recycling - Sector 2: Waste Recycling Center
 * 14) Monorail: Facility Transport
 * 15) Delta Labs - Level 1: Union Aerospace Research Division
 * 16) Delta Labs - Level 2a: Union Aerospace Research Division
 * 17) Delta Labs - Level 2b: Union Aerospace Research Division
 * 18) Delta Labs - Level 3: Union Aerospace Research Division
 * 19) Delta Labs - Level 4: Union Aerospace Research Division
 * 20) Hell
 * 21) Delta Complex: Union Aerospace Research Division
 * 22) Central Processing: Processing Distribution Center
 * 23) Central Processing: Primary Server Bank
 * 24) Site 3: Analysis Facility
 * 25) Caverns - Area 1: Excavation Transfer
 * 26) Caverns - Area 2: Artifact Excavation
 * 27) Primary Excavation: Artifact Dig

Xbox port
The Xbox version was sold in both a standard case, as well as a special edition sold in a metal case. The metal case edition had several extras—interviews, G4's Icons Doom episode, early artwork, and the full versions of The Ultimate Doom and Doom II. The Xbox Collectors edition includes two more levels, one in The Ultimate Doom (E1M10: Sewers) and one in Doom II (MAP33: Betray).

Due to console limitations, the Xbox port's textures were less detailed than that of the PC version. Some of the levels were split up into separate parts and other levels were condensed, taking out a couple of chunks that were present in the PC version to compensate for the memory limitation. Nonetheless, most reviewers were impressed that the Xbox had otherwise retained all of the other features, considering that its NV2A graphics processor (equivalent to an Nvidia GeForce 3, the original base card for Doom 3) was a generation behind the recommended video cards (ATI Radeon 9700 and GeForce 4 Ti) for the PC version. The NV2A processor was what distinguished the Xbox from the PlayStation 2 and GameCube, the latter two consoles were not considered for a Doom 3 port due to insufficient hardware. The PC version had been originally designed with the GeForce 3 in mind, but now that GPU is barely sufficient to run the game, a Radeon 9700 was used to run the E3 2002 demo.

The Xbox version has added co-op play, which required the modification of levels, such as widening corridors to comfortably accommodate a second player.

This version is compatible with Xbox 360.

Xbox controls

 * Left Thumbstick: Move
 * Right Thumbstick: Look
 * Click & Hold Left Thumbstick: Crouch
 * Click & Hold Right Thumbstick: Zoom
 * A: Jump
 * B: Previous Weapon
 * X: Reload
 * Y: Next Weapon
 * Left Trigger: Sprint
 * Right Trigger: Action
 * White (LB for 360): Equip/Unequip Flashlight
 * Black (RB for 360): PDA/Multiplayer Score
 * Start: Pause
 * Back: Save/Ready

The D-Pad arrows serve as hotkeys to select weapons instead of cycling through every weapon in inventory. Four weapons can be assigned. The weapon assigned to each arrow is customizable.

Doom 3 BFG Edition

 * Main article: Doom 3 BFG Edition

Doom 3 BFG Edition is a remastered edition of Doom 3 for the PC, Xbox 360, and the PlayStation 3. The game was released on October 16, 2012. It contains the Doom 3 expansion pack Resurrection of Evil, as well as a bonus campaign called The Lost Mission. In addition, it includes The Ultimate Doom, Doom II: Hell on Earth, and Doom II: No Rest for the Living.

Reception
Few games have polarized gaming as much as Doom 3 has, and many reactions to the game are in heavy contrast to one another.

Criticism
Some commonly named shortcomings of the game are:


 * Reliance on traditionally overused horror techniques such as pitch black darkness, limited use of the flashlight and stock horror movie clichés, which may make the game frustrating to play rather than scary or atmospheric.
 * Gameplay is overall slower and more restricted, thanks to the realistic movement and the reloading mechanism with the weapons.
 * The Shotgun, a staple primary weapon players enjoyed using in the classic games, has it's effectiveness reduced considerably to a simple close range weapon.
 * No ability to use the flashlight and the weapon at the same time, known as "No duct tape on Mars" problem, whereas today many real-life weapons have hands-free light attachments (as a result of this, many light-mods on the internet add a flashlight to the guns).
 * Somewhat stale storytelling techniques, forcing the player to read or listen to messages by hiding access codes in them, and a shortage of cutscenes providing story exposition, with one reviewer saying that adding clumsy storytelling to the game ending up weakening the experience.
 * Over-reliance on scripted sequences. Reviewers particularly criticized the monster ambushes that are triggered by the player, while some do fit in with the premises of the level (demonic enemies can be reasoned to come from flaming vats), other enemy spawn points are simply at where powerups are.
 * Somewhat limited use of physics, which was improved significantly in the Resurrection of Evil expansion.
 * A small multiplayer deathmatch mode of only a few people, stemming from Doom 3's focus on the single player experience.
 * No official cooperative gameplay in the PC version whereas the original Doom contained a cooperative mode. Co-op mode was included in the Xbox port of Doom 3, which required the redesign of maps to accommodate two players.

Some critical reviewers consider that the technological level of Doom 3 is similar to that of other games of 2004, and that features such as bump mapping had already become industry standard. For example, an often mentioned feature of Doom 3, per-pixel lighting and stencil shadowing, had already been implemented in some games released in 2003, even a budget title from Activision Value called Secret Service: Security Breach.

The BFG Edition includes some improvements based on feedback, most notably the ability to use a flashlight and a weapon at the same time.

Rebuttals to criticism
Many gamers argue the apparent shortcomings are not shortcomings at all, but are integral to the gameplay id determined to display for Doom 3.

Since Doom 3 is a remake of the original Doom - a game which did not have high-end concepts common in today's more complex games - remaking Doom with too much complexity would remove a key component that made Doom popular in the first place.

The deliberate slow pace, horror clichés, and overly scripted sequences (including the randomness of enemy spawning points) is designed to inspire terror. Every aspect of the game, from the lighting and sound to interactions and monster ambushes contribute to an overall feeling of fear and anxiety. 

The flashlight is a key element of Doom 3's gameplay: the player must balance between seeing the enemy, and defeating it. Almost every monster has glowing eyes, or some aspect of bio-luminescence which offers a target for the player. If weapons had a light attachment, this results in the mystery of "the unknown" to be less potent and frightening. Making things easier is the default flashlight toggle "F", which enables the player to switch very quickly between his weapon and the flashlight, if he is using the WASD keys and the mouse to move, similar to the rationale behind the use of the very frequently used "R" (reload weapon) key and the "C" (crouch) key. Additionally, muzzle flashes can be enabled for marginally better visibility while firing.

Another rebuttal concerns the story of Doom 3, which is done through the use of audio and video logs. The use of logs in this way is similar to the use of logs in System Shock 2. Players are free to not listen to the audio logs if they don't care about the story and just want to play the game.

A few of these criticisms of Doom 3 are based on expectations for other types of FPS games. During development, it was often compared with the equally anticipated Half-Life 2. Some have argued that since Doom 3 was released before Half-Life 2, many have come to expect things from it that they previously had expected from Half-Life 2. For example, the common complaint about the entry's lack of environment interactivity could be considered a subtle complaint that Doom 3 doesn't have a Half-Life 2-style "Gravity Gun", a weapon which can be used to throw or push many objects in the world, including small objects, cars, and organic lifeforms. Ironically, Doom 3 was said to have a "Gravity Gun" item designed long before Half-Life 2, but was not in the game proper. This weapon appears in the Doom 3 expansion known as Doom 3: Resurrection of Evil, which has drawn the ire of those who feel id is pandering to Half-Life 2 fans.

With regards to a minimal multiplayer mode, the designers intended that Doom 3 would be played and remembered primarily for its single-player story experience, as opposed to id Software's previous titles which were known far better for multiplayer deathmatch. (The follow-up Quake 4 would have a return to multiplayer focus using Doom 3's engine.) The Xbox port of Doom 3 did implement co-op mode but in order to make the co-op mode feasible and balance out gameplay, levels had to be redesigned to accommodate both players.

The main criticisms were addressed in DOOM) and Doom Eternal, which use much the same aesthetic of Doom 3 but make the game faster-paced and leaning more on combat, while PDAs are eliminated. Lore pickups are introduced in Doom Eternal, but as a sort of optional entertainment for the player, with no essential information within the lore required to progress in the game.

Sales
The game was a commercial success for id Software, with the planned total revenue estimated by Activision at $20 million. It was one of the top selling games of 2004, alongside Halo 2 for the Xbox and Half-Life 2. The financial success was bolstered by the near-record number of pre-orders placed for the game.

id Software also typically benefits from licensing the engine to other developers. Several games have already been developed using a modified Doom 3 engine, including Quake 4, Prey, Enemy Territory: Quake Wars, Wolfenstein, and Brink.

As of August 23, 2006 Doom 3 has garnered an average review score of 87%, according to 97 media outlets on GameRankings.com. By the same source, it is in the top 10 PC games of 2004.

E3 2002 Game Critics Awards: Best of Show, Best PC Game, Best Action Game, Special Commendation for Sound, Special Commendation for Graphics.

Doom 3 Timeline Events
Monday November 15th, 2145

6:18am - DarkStar arrives in Mars City Hangar

6:55am - Darkstar leaves for Burns Flat, Oklahoma, Earth (Mars-Earth trip takes 1 month)

8:00am - Energy Team Meeting in Delta Sector 1

8:30am - Atmosphere Monitoring Equipment Transfer (Communications Facility)

12:00pm - Sector 2 Preliminary and Decoherence Test (Delta 1)

1:00pm - Check all files for build (Delta 1)

1:20pm - Campbell initiates security lock down in Communications Transfer

2:30pm - Marine arrives at Delta Sector 1, Executive Personnel Tour (Delta 1)

3:30pm - Storage Crates Transfer (Communications Facility)

5:30pm - Shift 2 Energy and Administration Meetings (Delta 1)

9:00pm - Off Duty Employees Only: Jim's Birthday Party in Delta Access Lobby (Delta 1)

Tuesday November 16th, 2145

6:30am - Large Artifact Removal (Completed at 7:38am) Marine arrives at Caverns via lift from Site 3 Analysis Facility

8:00am - Final Artifact Removal (Caverns 1)

12:00pm - Construction Cotainer Transfer (Caverns 1)

6:30pm - Portable Equipment Removal (Caverns 1)

Saturday November 20th, 2145

9:36pm - Marine extracted from UAC base

May 1st 2146 - Orbital Probe records faint broadcast from the abandoned Site 1 Complex

August 8th 2146 - UAC Board of Directors renew Mars program

March 17th 2147 - Marine and his team are sent by Dr. Viktor Kharkov to investigate a hidden tunnel below the surface.

Mods

 * The Classic Doom for Doom 3 mod replays Knee-Deep in the Dead but with the new Doom 3 engine.
 * The Last Man Standing mod enables cooperative play, and introduces a new game type.
 * The Dark Mod a total conversion mod which converts Doom 3 into a game like Thief: The Dark Project
 * Hexen: Edge of Chaos a total conversion mod which converts Doom 3 into a game like Hexen: Beyond Heretic
 * Sikkmod a game-play and graphical enhancement mod that includes SSAO, DOF, and HDR
 * Bubba Lego-Tep starring Lego Elvis total conversion based on the film Bubba Ho-Tep starring Bruce Campbell

Other mods for Doom 3 include:
 * A mod that puts lights on the weapons (but which are less effective than the flashlight), colloquially known as the duct tape mod.
 * A mod that prevents the bodies of the monsters you killed from disappearing
 * A mod that makes the Cyberdemon at the end of the game vulnerable to weapons other than the Soul Cube
 * A mod featuring the Doom 3 weapons for Classic Doom source port ZDoom also exists. It includes several Doom 3 weapons (using sprite-based graphics and Decorate to recreate the weapon behavior) except for the grenades and Soul Cube. The mod works with both Doom and Doom II, though the mod lacks the super shotgun when played in Doom II.

Trivia

 * At the very beginning of the game, there are 2 posters for the UAC. One of them ironically says "One step closer to heaven".
 * The Doom community long predicted a sequel to Doom II, usually referring to it as Doom 2000. Some speculation is recorded in this Doomworld mailbag from 1998-08-18.
 * TimeSplitters: Future Perfect parodied the Doom 3 audio logs in the level "What Lies Below". In this level, Cortez can access a scientists' personal audio log, which contains his locker code (or, at the very least, several three-digit numbers which he believes are his locker combination). In addition, a small segment of this level's theme song can be heard in the background of the Doom 3 level Mars City.
 * The character of Dr. Reinhard in Evil Dead: Regeneration may be a parody of Dr. Betruger. Both share a similar physical appearance, including a severe cataract in one eye. Both men also started out good but turned evil when tempted by the forces of Hell.
 * The UAC is apparently the successor organization to NASA; in one of the videos, the UAC claims to have been the leader in space technology "since the dawn of the Space Age".
 * The airlocks display pressure in pounds per square inch, showing that UAC engineers still use US-Imperial units in the 22nd century. The pressure inside the complex is 14.7 psi as on Earth's surface, while the pressure of the Martian air is given as 0.13 psi, which is more or less the true real value. (The most likely metric equivalent used in that situation would have been the kilopascal or millibar.) On the EnPro Plant level, by contrast, the temperature of the reactor core is announced in degrees Celsius, although the Celsius scale is already used for most purposes in the United States that involve temperatures far above or below room temperature.
 * After returning to Mars from Hell, a terminal in the CPU Transfer Bay Entrance displays a red screen. An email can be downloaded from this terminal, containing a rather tongue-in-cheek message written by the demons on proper human sacrifice techniques.
 * In the final room before the Cyberdemon encounter, a small id Software logo can be found on one of the bricks in a corner. Approaching this turns the crosshair into a mouse arrow as would happen if the player approached a terminal. Clicking this opens a secret room which contains a PDA. Picking this PDA up downloads special "thank you" messages from the id Software staff.
 * The large Hell Gate that is present on the menu selection screen resembles the titular Stargate from the Stargate franchise, with the constellation markings replaced by runes.
 * The name 'Dr. Betruger' has a strong similarity to the German word 'Betrüger' which means 'deceiver' or 'impostor'.
 * If the player earns a score of 25,000 on the in-game arcade cabinet Super Turbo Turkey Puncher 3, an e-mail will be sent to the PDA congratulating on setting a new high score, being a shining example of humanity by punching defenseless turkeys, and losing two days of leave.
 * After receiving the PDA, the receptionist returns to typing on his screen. He types an e-mail message about the player arriving to Mars and being very rude for reading over his shoulder.
 * [//www.martianbuddy.com http://www.martianbuddy.com] is an actual website that provides the code to the two Martian Buddy lockers within the game.
 * Trying to access this website will redirect to Bethesda's main site.
 * In the Primary Excavation: Artifact Dig level, in the room with several tablets, one can be compared to the original Doom cover but with fewer demons and the Doomguy has the soul cube in his hands. It also has his head broken off.
 * The weapons in the Hell portion of Doom 3 feature only weapons that appeared in all of the Doom games (Fists, Pistol, Shotgun, Chaingun, Plasma Gun, Chainsaw, Rocket Launcher, and BFG9000).
 * During the very first levels, you can see some UAC workers located in places you cannot normally reach. After activating the noclip cheat code and getting to these areas, you can see that all of the "unreachable persons" share the name Joe.
 * Doom 3's working title during development was "Neo".
 * In the Alpha versions of Doom 3, most of the demons have their bodies intact upon defeating them instead of burning away in the final release.
 * Later during the game of Doom 3's Expansion Resurrection of Evil, the player teleports to parts of the UAC Base and it appears that the growth that had "infected" parts of the base had gotten worse over the course of time (6 months - 3 years) it was left abandoned.
 * Doom 3 is notably inspired by the 1998 first-person shooter Half-Life. This is apparent with the focusing of teleporters in the games, an elite military presence in both (HECU/Black Ops in Half-Life and Marines in Doom 3), usage of a monorail system, and the scientists prior knowledge and research of the major non-human faction (Xen in the case of Half-Life, and Hell in Doom's case).

References to Classic Doom
See main article: References to Classic Doom in Doom 3.

Expansion
See Doom 3: Resurrection of Evil.