There is one more Steam title which already Linux compatible and probably will be released some day.

One of Eugen System developers confirm it here:
Quote Originally Posted by Mawww
As it's main developer, I can confirm there is a Linux version of the game internally at Eugen Systems, I use it daily as I do my work under Linux. At the moment it is not sufficiently polished, and I cannot say anything about a potential release...

I would however be interested in knowing which distributions you are using, what are your graphic cards and drive
So if you want to see that game coming to Linux, serf to their forum and leave your comments/system configuration.