All Positech Strategy/Sim games by Positech are on sale for 50% off at Direct2Drive this weekend. A game of interest is Gratuitous Space Battles. It’s described as a hybrid RTS/Tower Defense game.
Note the 10% off promo coupons and the 15% off codes aren’t working on this game.
This game has a 72/100 metascore. The expansion DLCs for the game are 50% off too.
I’m about to post a few 20% off one-time use codes that will work on the game however, if you want to try to grab one of those.