Not sure what the problem is, I don't actually have a Linux machine -- I just press a button in Unity that says "Export to Linux" and hope for the best. You could always try the Windows version using Wine.
I see, I did some reading and apparently the 32 bit support of Unity on Linux is kinda borked (if I understood correctly), and since I'm stuck with a 32 version on my current laptop...
Oh well, I'll try wine.
Oh, game is awesome btw. Can't wait for the next updates. :D