UNIX systems were fairly well know for their games, remembering of course that all we had was a dumb terminal to work with. Still, the terminals of the time were mostly cursor addressable, so although there were no high resolution graphics, you could do some pretty nice stuff with character graphics.
In fact, it made game designers concentrate more on the story line and logic of a game and not the graphics and music. I think in many ways, the games were better thought out in the old days.
I have rebuilt a number of the classic adventure/dungeon games for the new Wyvern. Below I have included some pretty verbose descriptions from the original game designers/programmers.