Good, but...
In my opinion:
1) The handling of the tank is horrible. It handles almost like a real vehicle, where if you let go of the wheel, it'll still continue turning in that direction for awhile unless you turn it back. It may be realistic but it doesn't work for a game where you can't see the wheel and can't feel your hands on the wheel. It was more of a chore than fun.
2) This doesn't seem like a realistic project to undertake in flash. Now I know we're on Newgrounds and all, and telling someone to go off and learn a programming language really isn't feasible, but flash isn't really designed for this and there is too much that can go wrong. A lot of the things could be handled more easily in other programming languages, and in flash it's just too much work for too little of a result. You should look into Java for making a game like this online. You're essentially reinventing the wheel by creating a tile based game, and making it more difficult by creating it with a medium more suited for animation and simple programming than actual complex games.