For those who love their first-person dungeon crawlers, The 7th Circle actually looks pretty good and they recently added Linux support.
It's not going to win any awards for originality here, but 68k Studios seem to have created a reasonably good retro-inspired dungeon crawler. With traditional turn-based combat, more than 60 spells to wield, a crafting and upgrades system and so on it's pretty full on features.
Check out the trailer:
The developers claim it has "15 huge levels" along with a bunch of random generation, so each play-through should be different. Plenty of secrets to discover, hidden walls, timed events and more to find.
It released for Windows last month, with the Linux release only being announced today just over a month later. It seems to have gone under the radar for most, with it only currently having a few user reviews although they do paint a pretty good picture for it.
Find it on Steam.