Traps break this game. They are either unavoidable, completely hidden by the side of the level, or just plain hard to see. This would be a 4-5 star game if they were removed or changed. Now its just a 1-2 star game.
The ships movement needs to be far more responsive. Also a 2-3 second pause between waves would give you time to click on the upgrade screen. Also turrets seemed to be buggy for me. I like it, but it needs to be polished a little bit more.
polishing as we speak :) thanks for the feedback!