John Carmack, John Romero, Adrian Carmack, and Tom Hall leave Softdisk. Wolfenstein 3D ships in 1992 and proves the FPS market — but it's just the warmup act.

Doom 1.0 drops on December 10, 1993 — uploaded to an FTP server at the University of Wisconsin. The shareware model distributes Episode 1 free. FTP servers crash under demand. An estimated 10 million people download it in two months.

Doom's IPX network multiplayer and deathmatch mode ignite competitive online gaming. Office networks grind to a halt. The term "deathmatch" enters gaming vocabulary permanently.

Doom II ships retail-only and sells 2 million copies in its first year. It introduces the Super Shotgun, the Icon of Sin final boss, and larger open maps.

id Software releases the Doom source code under a non-commercial license (later GPL in 1999). Within days ports appear on Linux, BeOS, and dozens of platforms. ZDoom, PrBoom, GZDoom are born.

Doom 3 launches with cutting-edge lighting, oppressive darkness, and scripted scares. It sells 3.5 million copies but divides fans. The id Tech 4 engine is widely licensed.

Doom 2016 resurrects arena FPS with glory kills, demon speed, and constant forward pressure. Won multiple GOTY awards and is credited with single-handedly reviving the genre.

Doom Eternal raises mechanical complexity to its peak — resource management, platforming, and a weapon wheel that demands mastery. Sells over 3 million at launch.

The "It Runs Doom" meme documents the game running on pregnancy tests, ATMs, MIDI keyboards, and a John Deere tractor. The original WAD format is still actively used.

The franchise returns to its roots with medieval hell aesthetics, a shield saw, and ground-based combat. id Tech 8 pushes visual fidelity to new heights.