First of all, I'm new to the forum, but not to the program. I think Paint.NET has got a lot of potential. I'm Vittorio, from Italy, and I'm 13.
Looks cool, but why don't you add a 1 or 2 "Frosted Glass" filter on the black circle?
--- My result ---
I did like MadJik, but without the gaussian blur and with the frosted glass filter. I rotated the layer to fit the bullet holes to the car. I also used oil painting filter.