[fl7305]

You could easily write a RISC-V CPU emulator for your older/smaller machines, and run the original Nethack code compiled to RISC-V.

[anthk]

Under a 286? At time-freezing speeds. Minix 2 under a homebrew 16 bit CPU already was so-so in usability:

https://homebrewcpu.com/

[fl7305]

I think it would be well enough for Nethack.

Would be interesting if even a Z80 could run Nethack in a CPU emulator.