The first-person steampunk dungeon crawler Vaporum [Official Site] is showing signs of being released for Linux and it looks great.
The developer actually said back in September of last year, that a Linux (and other platforms) did depend on how the game did after the initial Windows release. I guess it did okay, since it's popped up on SteamDB as of 4 days ago, with more signs as well. As always, this isn't a guarantee it's coming, but it looks like work is going into it!
It has pretty good reviews overall, so we may take a look when it releases for Linux.
About the game:
Vaporum is a grid-based, single-player & single-character dungeon crawler RPG seen from the first person perspective in an original steampunk setting. Inspired by old-school games like Dungeon Master I and II, the Eye of the Beholder series, and the most recent Legend of Grimrock I and II. Stranded in the middle of an ocean, in front of a gigantic tower, the hero has to find out what the place is, what happened there, and most importantly, who he is.