[Cthulhu_]

The keyword / genre here is "Interactive Fiction"; MUDs fall in the same league as text based adventures of old (which later on started to add some graphics until they eventually evolved into e.g. the Monkey Island games), or even the choose-your-own-adventure (comic) books.

It's an older style of games, but honestly, I could have seen myself getting into this back when. It's tech that predates MMO's like WoW or Ultima Online. It's stuff that works everywhere.

And of course it's a different way to experience a game and its story. Dwarf Fortress also comes to mind, weirdly.