Not sure about Nethack, but you could actually try original Rogue — it should run even on an XT.

Niborius wrote on 2022-06-17, 14:32:

Hi! […]
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Hi!

I recently learned about Nethack and would like to get into it. However, Nethack 3.4.3 runs quite slow on my DOS machine. These are my specs:

486DLC/e 40MHz
1MB RAM
(probably irrelevant) Trident TVGA 8900D, 1MB

I learned that Nethack 3.4.3 recommends at least 4MB of ram.
Before I upgrade my machine, is there an older version of Nethack that is good and requires only 1Mb RAM?

Dwarf Fortress, sire?

^ Like your thinking kitten, but can DF run in 1MB? I don't think so.
I have a vague memory of playing NetHack with only 2MB but that was in the early nineties, thats about 30 yrs ago so...
If such version exists, it must be one of the very early ones (3.1.x 2.3e or earlier). EDIT: Yup apparently it does exist, see here.
If you're willing to go further back there's always the predecessor, simply called "Hack". That one oughta work.

EDIT: Here's something to check out...
Compiling old Nethack versions