interesting
While your inverse control scheme is an interesting idea I find that it doesn't work as well as the traditional WASD to move/mouse to aim. The offset keys offset it too much to aim precisely. Decreasing the angle of offset by 50% per button press would help with that issue.
Keeping your money after you lose is nice. It helped me get through some levels that I was having trouble with.
I wish that it was a little slower or you had a larger playing screen. As it is it's almost impossible to dodge enemies/attacks so the tank build is the most effective type.
I also found the font type and size difficult to read.
Overall it was a pretty good game. Good job with this.