MicroPython (lexer, compiler and VM) on the SNES: 3.58 MHz 65816, 56 KB Python heap, 16-bit int. The REPL runs right inside the post via EmulatorJS and also works on real hardware via flashcart.

I did this as a benchmark for Claude Fable. When the export ban hit, switching to Opus got the project stuck for three weeks; Fable came back and found the real bug in ninety minutes.

Along the way: 23 compiler bugs and 4 MicroPython bugs, each root-caused with a minimal reproducer and filed upstream.

If you run it on real hardware, I want a picture!

That's absolutely crazy! Compiler bugs and micropython bugs???

On the other end of the cost scale right now, I'm running multiple Deepseek V4 Flash instances basically constantly practically for free (because I'm poor right now) and I'm impressed by that too.