There are a few bugs
First: If you click rapidly, the bullets will keep resetting back to the one just outside of the barrel.
Second: Explosions cause missiles and bullets to stop. This can cause a huge waste of missiles, and render some opponenets temporarily invulnerable.
Third: If you fire an arc of missiles during the "Go to next level" scene, and then hit the continue button, the missiles will continue to fly and destroy anything they touch. This is a way to fire more than 50 missiles per round.
Other than that it's a very fun game, great work.