Very, very bad. It's actually easier to win by running over everything instead of shooting, bullets don't affect the opponent's tanks in any way, and you get sent back to your start position when you run into the AI tank.
Frankly, I don't really see the point to recreating the games that come with your operating system, especially since you can't improve on them, and in fact have trouble getting it to work as smoothly as the Microsoft version. But, I'll give you a 3 for effort.
There really is no hope for this game. The concept had no potential whatsoever. You may have decent graphics and music, but there is absolutely no way you can improve this game without scrapping the core mechanic entirely. 1/5.