Defense Grid

CSTW is a good game, but it is their 2nd of 4 games, and they keep getting better in mechanical quality and execution, and their 5th game coming out soon (Cosmic Star Heroine) is going to be utterly fantastic. The 3rd and 4th game are tied to the Penny Arcade licensing which does a lot to change their appeal in some ways, but the next one is going to be entirely their own IP again.