Its been a while since I did a Gamer's Review and I did not know this was in a previous humble indie bundle years back until now. It's Revenge of the Titans from Puppy Games. Its very much a tower defense type of game and its you versus hordes of rampaging titans from another planet on a dystopian earth. All the levels involve you defending the last outpost in a real world city with an army of robotic turrets, which can be researched and upgraded. To make things harder...the titans rush in on all sides and get stronger with each passing level.
On the art style front, its very much paying tribute to retro gaming as everything is 8-bit sprites and with matching sound effects, 8-bit classical music, and humans speaking in bloops and bleeps. So far I didn't expect this game to be so fun!