At first I thought this game was too hard, but now i kinda enjoy the difficulty and the way it's all set up. I also didn't realize there was a second tab in the tower upgrade panel on the right til now...
I think kar achievement may still not be working, cause after getting it my kar still functions the same, and it's still impossible to do the speed challenge for it.
The damage honestly has to be fixed. I liked this game pretty much before, but at this point it's borderline unplayable with how little damage you deal.