Freedoom
Doom, in the browser, with god mode wired on from the first tic.
What you play here is Freedoom, a free replacement for the original Doom game data. It runs on the same engine and keeps the same feel, but every sprite, texture, sound and level is new and freely licensed, so it can be shipped on a page like this one.
Freedoom exists because id Software opened the Doom engine source in 1997 but kept the game data closed. Volunteers have been rebuilding that data on their own time since 2001: sprites, textures, music and maps drawn from zero, always reusing the original resource names so the engine and old mods find what they expect. It is all developed in the open and packed into a WAD with DeuTex. This page serves Phase 1, the set shaped after the original episodic Doom.
Engine doomgeneric compiled to WebAssembly, under GPLv2. Assets from Freedoom 0.13.0, under its license. No original id Software file is distributed here.