Cubemen 2 was just released in the Linux section of the Steam store. Pick it up for $5.99 (-25% off) until April 15th.
About:
Cubemen 2 is a fast paced, action packed, original 3D Strategy game where you use your little Cubemen units to defend and attack enemies in a range of awesome game modes including CTF, Skirmish, Territory and more.
Website:
cubemen2.com