This was a great game. I wish I could have used wasd, but that's probably a personal gripe. I think that using "Up" or forward for the thruster would have made more sense, and put the button as the bullet. I found myself wasting bullets on accident because I was trying to thrust real quick haha. After 8 levels I got used to it, but I think making it more intuitive would lessen the time it takes to get to the real fun, your cool game! :D
edit: radar and lock on are freaking amazing. Great job with those features, nailed em :)