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 in the UAC research center on Mars, is a re-imagining of the original Doom, with a completely new game engine and graphics.

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 it 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 at id, the "tripod of features" in Doom 3 technology 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.

id Tech 4 engine
id Tech 4 (AKA the "Doom 3 engine") began as an enhancement to id Tech 3 which was used in Quake III Arena. Originally it was planned to be a complete rewrite of the engine's renderer, while still retaining other subsystems, such as file access, and memory management. After the new renderer was functional, however, the decision was made to switch from C to the C++ programming language, necessitating a complete restructuring and rewrite of the rest of the engine; today, while the Doom 3 engine contains code from id Tech 3, much of it has had to be rewritten.

Unlike the preceding and widely-used id Tech 3 (Quake III Engine) and id Tech 2 (Quake II Engine), the Doom 3 engine has had somewhat less success in licensing to third parties. This is especially apparent in comparison to its direct competitor, the Unreal III engine. While id Tech 4 had taken a new direction with its dynamic per-pixel lighting, this unconventional feature had steeper hardware requirements and was initially only useful in "spooky games", whereas an increasing number of developers preferred conventional engines that could render large outdoor areas. Indeed, due to the long release time between id Tech 3 and 4 (1999-2004), id Software did not have anything competitive when Epic Games released Unreal Engine 2 in fall 2002; game developers used to UE 2 largely went onto Unreal Engine 3.

Like its predecessors, id Tech 4 will eventually be released as open source. At the QuakeCon 2007, John Carmack the lead graphics engine developer at id, said to LinuxGames: "I mean I won't commit to a date, but the Doom 3 stuff will be open source."

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 the 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 with Dr. Betruger (with spectacles) pushing his way past a couple security guard to initiate a test run. However, computer systems starting 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, imps, and commandos, before running out of ammo and being killed by a Hell Knight, who then rips off the player's head (the camera view) and eating 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 III 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


Prior the events of the game the UAC's original project involving the exploration of Mars was to transform it into an inhabitable planet with the creation of Hydrocon and breathable atmosphere.

However, the initial construction of Mars City accidentally unearthed underground artifacts and structures that revealed the existence of an ancient Martian civilization. In response, the UAC modified it's original project on Mars to function as an Archeological Excavation Site, with labs and general posts established in different locations. The explorations of the caverns in 2104 lead to the discovery of ancient artifact codenamed U1, the Soul Cube, along with stone tablets written by the ancient M artian civilization.

The tablets contained knowledge and technical information on a powerful teleportation technology. As a result of these discoveries, the UAC's primary goal on Mars changed to the recreation of the technology, with the supervision of UAC's brightest scientist and creator of the Hydrocon, Dr. Malcolm Betruger. The development began in the secured location known as Delta Labs. At the same time, scientists like Pierce Rogers were in charge of the archeological effort, mainly with the translation of the glyphs contained on the stone tablets. These glyphs warned of the potential risks of using the teleportation technology, which was the reason why the Martian civilization became extinct.

Once activated, the teleportation technology wasn't exactly a teleportation, it worked as portal device which led into another dimension. After several tests with cameras and animal subjects, the scientists discovered that this dimesion was filled with sweltering heat and hideous creatures. Betruger and other Delta Labs personal immediately began to try to explore this dimension using human subjects. However, many of the people that returned from the tests suffered from immense psychological trauma which lead to their deaths, many others not returning at all. As the tests occoured, the scientists at Site 3 were already translating the warning, but by the time they discovered the horrors of what happened with the martian civilization, it was already too late. T he teleportation project had already become focused on exploring and exploiting the other dimension discoveries, such as bringing back dead and live species and long travel on the dimesion. Not long after, the whole Mars Base showed having strange problems with light and energy, several personal reporting frightening situations and asking for transfer off of Mars.

Betruger himself became obsessed with the other dimension, becoming corrupted by the power and authority he held, using it to control Mars City and hide the horrors of his discoveries from Earth. Delta Labs scientists such Ian McCormick and Jonathan Ishii were already theoryzing that the dimesion was, in fact, Hell, but they were too scared to send their theories to Earth. One scientist however, named Dr. Elizabeth McNeil, challenged Betruger's authority and called the UAC Board to stop the Delta Labs project. Discovering this, Betruger expelled McNeil from Mars, and, not long after, he entered into the portal himself. When he came back, he was a different person. A couple of days later, the UAC Board of Directors on Earth apointed the company's lawyer and councilor Elliot Swann and his bodyguard Jack Campbell to enact 'damage control' for the whole Mars operation. On the date of November 15, 2145, they arrived on Mars City on the ship Darkstar.

The protagonist is, once again, a nameless space marine holding the rank of Corporal who came along with Swann and Campbell aboard the Darkstar. This marine was called to replace another who died during an operation. As he is as signed by Master Sergeant Kelly, a.k.a “Sarge”, to find a missing scientist named Jonathan Ishii that was last seen in the old Communications Facility, Councilor Swann and Campbell argue with Betruger about the m any incidents happening throughout the base, along with frightened employees and rumors of what is happening in the Delta Labs. Betruger replies to Swann that "amazing thing will happen here soon" and to stand out of his way.

When the Marine found Ishii, he babbles about sending out a warning to Delta Labs - Level 4 and that'' "the Devil is real. I know, I bent his cage." '' With those words, Hell erupts from the main experimental gateway, sending a shock wave through the complex, along with glowing pentagrams and scores of evil ghost skulls that transform nearly every human into zombies, including Ishii. T he remaining staff are killed off by the attacking demons with o nly a few scattered squads remaining, Bravo Team being the main one. After returning to the Reception area, the Marine is ordered by Sarge to regroup with Bravo Team and help them send a distress signal to the space fleet. At the same time, Swann again argues with Betruger in a video phone conference, Betruger being rather calm about the situation, and claiming that it is under control. Knowing that Betruger is somehow linked to the invasion, Swann and Campbell also go to the Communications Facility to prevent anyone else from coming to Mars.

The Marine's effort to regroup with any remaining marines ends in vain as Hell has hit hard, killing or possesing the human population on Mars and leaving only a handfull of humans who, with futile effort, hide or lock themselves in the most secure areas that they can reach. Passing through the Administration and Alpha Labs areas, the Marine encounters many demons and zombie enemies, some of which are lead by a powerfull Vagary. After reaching the EnPro Facility, the Bravo Team is attacked and killed by a group of Wraiths and Imps, with the exception of one surviving marine who plays dead to hide the distress card from Swann and Campbell when they pass by him. When the Marine reaches the slaughter of Bravo Team, this survivor gives the distress card to him and succumbs to his wounds. When the Marine finally reaches Communications, however, Campbell has already destroyed the main console with his BFG 9000. Sarge then quickly orders the Marine to go to the a isolate satelite tower and send the transmission for reinforcements. There, the Marine is conflicted by a moral decision, when Swann contacts him on a video conference, who asks the marine to stop the transmission, since they "...don't know what the hell is going here, and until we do, this facility will remain on UAC control".

Sending the message or not, the Marine is ordered by Swann/Sarge to go to Delta Labs and help stop the invasion. After receiving security clearence to the Monorail, he is trapped by Betruger himself on the Waste Recycling Center. Betruger taunts the Marine, revealing that he commands the monsters that have overrun the base and saying that he already send a transmission to the fleet, and his wainting them to show up to hijack their spaceships and attack civilians on Earth. Betruger also uses his powers to transform wounded marines into his Commando servants. After escaping the Center, the Marine uses the monorail and finally reaches Delta Labs.

On Delta Labs, the Marine meets Sarge on another video conference, but he is different, talking more cold and dark. They agree to meet at one point on Delta, but Sarge doesn't show up. On the Delta Labs - Level 2, the Marine encounters Ian McCormick, who explains to him the background story about the teleportation experiments and the Hell invasion, and helps the Marine teleport himself to another sectors of Delta. McCormick also explains that when Betruger unleashed the invasion, he went to Hell with the artifact from the archaeological digs called the Soul Cube, and he believes that that artifact is the only way to stop the invasion. After going thorugh the small portal pads on Delta Labs - Level 3, the Marine reaches the main gateway on Delta Labs - Level 4, but Betruger activates it, sending two Hell Knights against him. After the Marine kills them, the gateway sends him to Hell.

In Hell, he fights against many of it's legions, but manages to find the Soul Cube, who is protected by the Guardian of Hell. After destroying him, the Marine recovers the artifact and get back to Mars. Shortly after his return, Betruger taunts him saying that gateway is useless since there is another portal called Hell Gate capable of bring milions of demons to our universe. Going through many areas of Delta Complex, the Marine finds Swann badly injured. Swann says that Sarge has turned evil and is now on Betruger’s side, and that Campbell went to hunt him. He also reveals that the demon's plan was always to get to Earth, since they  "were there before, lost in the dunes of times" and the marine must help Campbell against Sarge. He gives to the Marine his PDA, saying that he is gonna try to make out on his own. Using his PDA, the Marine reaches the CPU Complex, only to find Campbell on his deathbed, mortally wounded by Sarge. Before his death, Campbell warns the Marine that Sarge stole his BFG 9000. After killing Sarge, now know as Sabaoth, on the CPU Banks, the Marine goes to Site 3.

There, he finds the archeologist Pierce Rogers, who explains to him that the ancient Martians used both religion and science to create portals through the planets of the solar system - including Earth itself. However, these portals opened gates to Hell, which invaded the whole planet just like the Mars Base. The Martians, on the ultimate act of sacrifice, created the Soul Cube and put their souls on it, energizing it. Then, the most powerful Martian warrior used it to drive the demons back to Hell. The few Martians burried their warrior along with the Soul Cube and the stone tablets to alert anyone of the dangers of the misues of their technology. Since Mars become a desolate planet, they fled to another planets - including Earth, which Rogers believes that humans are actually descedents of Martians. Pierce gives to the Marine his security clearence and lockes himself up, saying that only the Soul Cube is capable of stoping the Hell Gate.

After passing though many caves underground, the Marine finally reaches the Primary Dig Site, where he discovers a section of Hell that has crept into the Martian underground and deep within the bowels of this Hellscape. There, he encounters the invulnerable Cyberdemon, who was guarding the Hell Hole — a enormous portal to Hell. Using the Soul Cube, the Marine defeats the Cyberdemon, and the Cube itself seals the Hell Hole forever.

Afterwards, on November 20, 2145, the Recon Zulu marine team and their sentry drones arrive on Mars City to secure the base. They discover the Marine on Delta Labs as the lone survivor, since the others UAC personal were found killed - including Councilor Swann, who died from his wounds. Recon Zulu team also states that they didn't found Dr. Betruger and neither know his whereabout.

The game ends on Hell, revealing that Betruger has now becomed the dragon-like demon 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 story-boarding 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.

Similar to the story of the original Doom, the game focuses on the marine who is transferred to Mars 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.) Unlike classic Doom, Doom 3's Demons from Hell have their bodies dissolve when they die, except zombies and certain bosses.

In both cases, the protagonist visits Hell. In the original Doom, it is the third episode, Inferno (Ultimate Doom adds a fourth, Thy Flesh Consumed, which takes place 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), but Doom 3's Hell level is much longer and more intense than the others, and with screaming of damned souls. It also has a boss called the Guardian. Other bosses include the Spider Queen, or Vagary (inspired by Dungeons and Dragons' Drider (a dark-elf/spider hybrid), Quake's Vore, (though the Vagary can also be seen as an apparent nod to the spiderdemon from the original Doom as well as Shelob from Lord of the Rings), a tank-like cyborg called Sabaoth and the final boss, the Cyberdemon.

Unlike in previous id games, there are now cut scenes 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, and security personnel at the Mars base. The messages explain the background story, show the feelings and 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 and 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. 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. Almost all of the game is extremely dark, and there is no Light amplification visor, nor do weapons have a flashlight attachment. Instead the player must rely on, rather infamously, 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 is 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 III; this omission was notable as it was a FAQ. As in previous Quake titles, Doom 3's rocket launcher allows rocket-jumping, but it is of little or no use in closed levels. The pistol, machine gun, and chaingun each use different calibers, therefore they do not share the same ammo pool as in earlier Doom games.This is also the case with the Plasma gun and the BFG. Also introduced are drones and sentry bots that will aid player as a "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
 * BFG 9000
 * Chainsaw
 * Grenades*
 * Soul Cube*

Monsters
Doom 3 includes updated versions of many monsters from the original games. Some of these, such as the Demon and the Hell Knight, are very different from their predecessors.


 * Arch-vile
 * Cacodemon
 * Cyberdemon
 * Demon
 * Hell knight
 * Imp
 * Lost soul
 * Mancubus
 * Revenant
 * Zombie
 * Chainsaw zombie
 * Fat zombie
 * Flaming zombie
 * Morgue zombie
 * Zombie commando
 * Zombie security guard

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 Ultimate Doom and Doom II. The Xbox Collectors edition includes two more levels, one in Ultimate Doom (E1M10: Sewers) and one in Doom II (MAP33: Betray).

The Xbox port's textures are less detailed than that of the PC version and splits many levels up into separate parts due to console limitations. Even though the levels are split up, some levels have been rearranged and some areas have been simplified presumably because the Xbox hardware would suffer otherwise. 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.

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.
 * Repetitive gameplay, similar linear levels during parts of the game.
 * Slow movement unlike the faster play speed of Doom, Doom 2 and the Quake series
 * 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 cut-scenes providing story exposition, with one reviewer saying that adding clumsy storytelling to the game ending up weakening the experience.
 * Poor monster AI and 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.
 * All weapons are direct-fire, point-and-shoot weapons with no alternate firing modes without any variation or innovation.
 * Slow ammo reload times that too often caused ranged fights to become blind button-mashing melees
 * 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.

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. Ken Levine, lead designer of System Shock 2, said of the logs in Doom 3 "It amazed me when I played Doom 3 that they didn't mix their recordings into the ambient space of the world. The people sound like they're in a recording booth."

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 Doom 3'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.

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.

Trivia

 * At the very beginning of the game, there are 2 posters for 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).
 * The character of Dr. Reinhard in Evil Dead: Regeneration may be a parody of Dr. Betruger. Both share a similar physical appearance, including a solid white 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 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. On the EnPro Plant level, however, the temperature of the reactor core is announced in degrees Celsius.
 * A terminal after returning to Mars from Hell displays a red screen. An email can be downloaded from this terminal, containing a rather tongue-in-cheek message written by the Hell 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 Stargate from the movie/television Stargate franchise, with the constellation markings replaced by runes.
 * The name 'Dr. Betruger' has a strong similarity to the German word 'Betrüger' which means 'traitor'.
 * If the player earns a score of 25,000 on the in-game arcade game 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 character 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.
 * http://www.martianbuddy.com is an actual website that provides the code to the two Martian Buddy lockers within the game.
 * After receiving the pistol, you can kill the civilian working on the crane and take his PDA.
 * 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 level of Doom 3 features 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 "unreachable persons" share the name Joe.

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.

Other mods for Doom 3 include:
 * A mod that puts lights on the weapons (but which are less effective than the flashlight)
 * 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 with Doom II.

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

Expansion
See Doom 3: Resurrection of Evil.