Doom is a first-person shooter developed and published by id Software, released in December 1993 as shareware. Players fight through Mars research facilities and hellscapes, armed with shotguns and rocket launchers against an invasion of demons. It popularised the first-person shooter genre, established multiplayer deathmatch as a gaming staple, and remains one of the most influential games ever made.
Doom was developed by id Software — John Carmack, John Romero, Adrian Carmack, and Sandy Petersen — and released on 10 December 1993 as shareware, distributed freely over the internet and FTP servers. Players control an unnamed space marine — retrospectively named Doomguy — fighting through the Phobos and Deimos moons of Mars and then Hell itself after a teleportation experiment opens a gateway to demonic forces.
Doom moved at a speed no previous first-person game had achieved. Carmack's engine — with its pseudo-3D rendering, texture-mapped walls, and variable lighting — produced a sense of spatial depth and momentum that felt genuinely new. Combat was fast and demanded constant movement; standing still was fatal. The arsenal escalated from pistol to shotgun to chaingun to rocket launcher to BFG 9000, each weapon carving through enemies with visceral, tactile impact. Level design by Romero and Petersen introduced secrets, branching routes, and environmental storytelling that gave each map a character beyond its function.
Doom's deathmatch mode — up to four players competing over a local network — is widely credited with creating the competitive multiplayer culture that defines gaming today. Its open WAD file format spawned one of the first major modding communities; tens of thousands of user-made maps and total conversions exist. The engine was released as open source in 1997, and Doom has since been ported to virtually every platform with a processor.
Doom is ranked #13 on Rolling Stone's 2025 list of the 50 Greatest Video Games of All Time. It defined the first-person shooter genre, demonstrated that PC games could be distributed outside retail, and launched id Software as one of the most technically ambitious studios in the industry. Every FPS made since operates in its shadow.