With one third of the game, nine levels, distributed as shareware, Doom was played by an estimated 10 million people within two years of its release, popularizing the mode of gameplay and spawning a gaming subculture. 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 release of the original game featuring a fourth episode, was released in 1995 and sold at retail.

The original game is divided into three nine-level episodes and distributed via shareware and mail order.

It is considered one of the most significant and influential titles in the video game industry, for having ushered in the popularity of the first-person shooter genre. WMS Industries Inc., Valve Corporation, Ocean Software, Midway Games, Virgin Interactive, GT Interactive Software, Bethesda Softworks, Activision, id Software, Sega, Atariĭoom is a 1993 science fiction horror-themed first-person shooter video game by id Software.