I know what it is, but I never played it! Used to play some of the early derivatives of Nethack on our old 8088 PC though...
Yep, that's where I got started. Used to just be called Hack, and there was another similar one that began with an M but that I can't recall...though it seems like it MIGHT have been Moria!
The original version we had ran from two 5.25" floppies, one in each drive, and in spite of being primitive graphics (ASCII characters, as is the current version, actually), still ran incredibly slowly, especially on levels with lots of beasties. You could tell when a hoard of orcs approached, as the system would slow to a crawl!