Daring coder gets Doom running with regular expressions at 180 seconds per frame, like playing 'correspondence chess with a shotgun' — nearly 14 million substitutions to render a frame at 80,000 substitutions per second

Artem Lytkin built a Doom engine entirely with regular expressions over a 96 MB text string.

The setup simulates CPU registers, memory, video output, and game data, and can render byte-identical frames.

It works, but very slowly: about 80,000 substitutions per second and roughly 14 million substitutions per frame, taking around 180 seconds.

The project highlights how far text processing can be pushed and how unconventional emulation can still run a real game.