Perfect
1. It's simple.
2. The graphics fit the game style
3. The graphics progress with Insanity
Another thing I'd like to comment on is the scoring. Though the game is somewhat difficult at first, creating a strategy gets you a very good score. Don't complain if you get 200 at first. Eventually, I was able to get upwards of 500.
John, you should make a Luminara/Sixty series. And happy birthday.