Doom is a first-person shooter game developed and published by id Software. Released on December 10, 1993, for 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.

A first-person shooter (FPS) is a video game centered on gun fighting and other weapon-based combat seen from a first-person perspective, with the player experiencing the action directly through the eyes of the main character. This genre shares multiple common traits with other shooter games, and in turn falls under the action games category. Since the genre's inception, advanced 3D and pseudo-3D graphics have proven fundamental to allow a reasonable level of immersion in the game world, and this type of game helped pushing technology progressively further, challenging hardware developers worldwide to introduce numerous innovations in the field of graphics processing units. Multiplayer gaming has been an integral part of the experience, and became even more prominent with the diffusion of internet connectivity in recent years.