

The Doom franchise continued with the follow-up Doom II: Hell on Earth (1994) and numerous expansion packs, including Master Levels for Doom II (1995) and Final Doom (1996). Its graphic violence and hellish imagery made it the subject of considerable controversy. As a sign of its effect on the industry, FPS games from the genre's boom in the 1990s, helped in no small part by the game's release, became known simply as "Doom clones". Doom made a massive global impact: it popularized the business model of online distribution it popularized the FPS genre of gameplay and spawned a gaming subculture and it pioneered the technologies of immersive 3D graphics, networked multiplayer gaming, and support for customized additions and modifications via packaged files in a data archive ("WADs") which are now called downloadable content (DLC). With one entire third of the game (nine levels) freely distributed as shareware, it was played by an estimated 15–20 million people within two years of its release.


In Doom, players assume the role of an unnamed space marine, who became popularly known as "Doomguy", fighting his way through hordes of invading demons from Hell. The Ultimate Doom, an updated version featuring a fourth episode, was released in 1995 and sold at retail. The original game was divided into three nine-level episodes and was distributed via shareware and mail order. It is considered one of the most significant and influential titles in video game history for having helped to pioneer, along with the 1992 game Wolfenstein 3D, the now-ubiquitous FPS gameplay type, and has been frequently cited as one of the greatest video games of all time. Doom (typeset as DOOM in official documents and stylized as DooM in other media) is a 1993 first-person shooter (FPS) video game developed by id Software for MS-DOS.
