Nice idea with the tetris style fitting of guns in your inventory, I like how you can combine them to incerementally upgrade your guns. I think if you wanted to improve the game it could do with something to do during the waves, maybe aiming the guns to some time of quicktime event to get a boost / explode enemies. Also, is there a way to fail / dye? Enemies seemed to reach me and I didn't notice any downsides when that happened.