Dominic Szablewski built this for js13kGames in 2021, a competition where the entire entry must fit in 13 kilobytes.
It is Quake. Not a tribute or a lookalike: a first-person shooter with levels, enemies, weapons, sound and a soundtrack, in less space than a single texture from the game it is imitating. Everything is generated at load time from a few hundred bytes of parameters, because there was no room to store any of it.
Enter fullscreen before you play: it needs pointer lock to aim.
