Doom runs on all sorts of things, from web browser logs to lawnmowers. It now runs on toothbrushes, too, thanks to Aaron Christophel. Doom runs rather well on the gadget, which features an ESP32-C3 system-on-a-chip with 4MB of flash memory.
The threshold of absurdity. What is the hypothetical minimum for the "Doom running on n" meme to reproduce? I might suggest a display (itself with some minimum identifiable resolution) on the assumption that we need to see Doom and might assume that even display controllers will soon be able to run Doom by themselves. But there are several assumptions baked into this that might be circumvented.
