Medium was way too easy
First off, the problems. When you bought the railgun, you couldn't switch the weapons back and forth, a small but annoying problem.
I also gained all of the upgrades rather quickly, almost too quickly. I found myself having 100,000+ dollars with nothing to buy except railgun ammo, a rather dull experience there.
Other than that, it was a great game. Great perspective. I loved the camera and how the shots had to be timed. Not many games have that, it's a great diversion from the usual. It was also very interesting how it coincided with Indestruc2Tank. A great take off.
Overall, a fun little game if you have the proper background knowledge. A few small problems, but nothing major. 4/5