Successfully ran "DOOM" using only regular expressions, taking about 180 seconds to render one frame

Developer Artem Litkin released “DOOM on regex,” a demo that runs DOOM using only regex search-and-replace operations.

The project builds a virtual 32-bit CPU called RVM-1 and stores CPU state and game data in a single ~96.6 MB string.

Execution advances through 544 replacement rules; rendering one frame takes about 13.99 million replacements and roughly 180 seconds.

The demo was run in parallel on five machines and verified to match standard DOOM byte-for-byte and by SHA-256.