Very fun game. The only thing I would tweak is the shooting function. Perhaps a button you can click to turn autofire on or off, since I kept wanting to keep autofire off but it kept switching on on me. Setting it as the same button as the fire button itself isn't quite the best option. Also, the missiles got very annoying by constantly firing. Perhaps you could either make them only fire when you're firing your bullets, or they can only fire when there's enemies on the screen.