I couldn't really enjoy it...
I have a laptop so I couldn't handle the levels too good, but the game design is very good, the idea and everything is well put into place.
You should make a Pick-A-Color Palette to change the color of your brush, and the tanks should be colored according to their skill level (hard to destroy tanx = red ; easy to destroy tanx = green)!
I hope you'll make a sequel and read my suggestions, even though here I gave you an 8, I voted 5/5!