John Romero in the context of "Id Software"

Doom is a 1993 first-person shooter game developed and published by id Software for MS-DOS. It is the first installment in the Doom franchise. The player assumes the role of a space marine, later unofficially referred to as Doomguy, fighting through hordes of undead humans and invading demons. The game begins on the moons of Mars and finishes in hell, with the player traversing each level to find its exit or defeat its final boss. It is an early example of 3D graphics in video games, and has enemies and objects as 2D images, a technique sometimes referred to as 2.5D graphics.

Doom was the third major independent release by id Software, after Commander Keen (1990–1991) and Wolfenstein 3D (1992). In May 1992, id started developing a darker game focused on fighting demons with technology, using a new 3D game engine from the lead programmer, John Carmack. The designer Tom Hall initially wrote a science fiction plot, but he and most of the story were removed from the project, with the final game featuring an action-heavy design by John Romero and Sandy Petersen. Id published Doom as a set of three episodes under the shareware model, marketing the full game by releasing the first episode free. A retail version with an additional episode was published in 1995 by GT Interactive as The Ultimate Doom.

Doom (stylized as DOOM) is an American media franchise created by John Carmack, John Romero, Adrian Carmack, Kevin Cloud, and Tom Hall. The series usually focuses on the exploits of an unnamed space marine (often referred to as Doomguy, Doom Marine, or Doom Slayer) operating under the auspices of the Union Aerospace Corporation (UAC), who fights hordes of demons and the undead to save Earth from an apocalyptic invasion.

The original Doom is considered one of the first pioneering first-person shooter games, introducing IBM-compatible computers to features such as 3D graphics, third-dimension spatiality, networked multiplayer gameplay, and support for player-created modifications with the Doom WAD format. Over ten million copies of games in the Doom series have been sold; the series has spawned numerous sequels, novels, comic books, board games, and film adaptations.

Doomguy or Doom Slayer is the protagonist of the Doom franchise by id Software. He was created by American video game designer John Romero and was introduced as the player character in the original 1993 video game Doom. Within the Doom series, Doomguy is a demon hunting space marine dressed in green combat armor who rarely speaks on-screen. In Doom Eternal, he is voiced by Matthew Waterson and Jason E. Kelley in that game's downloadable content The Ancient Gods: Part Two., followed by the 2025 prequel Doom: The Dark Ages. A different character with a role similar to that of Doomguy was portrayed by Karl Urban in the 2005 film adaptation.

Doomguy has appeared as a guest character in several other games, including Quake and Tony Hawk's Pro Skater as well as including his likeness as a customizable skin for the Mii Gunner character in Super Smash Bros. Ultimate, and being added as an outfit in Fall Guys and Fortnite. He has received mainly positive reviews.

Wolfenstein 3D is a 1992 first-person shooter game developed by id Software and published by Apogee Software and FormGen for DOS. It was inspired by the 1981 Muse Software video game Castle Wolfenstein, and is the third installment in the Wolfenstein series. In Wolfenstein 3D, the player assumes the role of Allied spy William "B.J." Blazkowicz during World War II as he escapes from the Nazi German prison Castle Wolfenstein and carries out a series of crucial missions against the Nazis. The player traverses each of the game's levels to find an elevator to the next level or kill a final boss, fighting Nazi soldiers, dogs, and other enemies with a knife and a variety of guns.

Wolfenstein 3D was the second major independent release by id Software, after the Commander Keen series of episodes. In mid-1991, programmer John Carmack experimented with making a fast 3D game engine by restricting the gameplay and viewpoint to a single plane, producing Hovertank 3D and Catacomb 3-D as prototypes. After a design session prompted the company to shift from the family-friendly Keen to a more violent theme, programmer John Romero suggested remaking the 1981 stealth shooter Castle Wolfenstein as a fast-paced action game. He and designer Tom Hall designed the game, built on Carmack's engine, to be fast and violent, unlike other computer games on the market at the time. Wolfenstein 3D features artwork by Adrian Carmack and sound effects and music by Bobby Prince. The game was released through Apogee in two sets of three episodes under the shareware model, in which the first episode is released for free to drive interest in paying for the rest. An additional episode, Spear of Destiny, was released as a stand-alone retail title through FormGen.

Tom Hall is an American video game designer best known as a co-founder of id Software and designer on classic titles such as Doom, Wolfenstein 3D and Commander Keen. He has also been the co-founder of Ion Storm, together with his friend and colleague John Romero. During his years in the company, Hall designed and produced Anachronox and was also actively involved in the development of Deus Ex.