Hey, the idea of this game is really great, it have everything to be very fun. But it needs just a little more "flavoring". Try to make better grafics for missiles, cannon and the menus. Give more life to the initial page and fix the problem that makes game crash when you die. A simple tutorial would be grat too! Good work.
Rate my game too if you can :D
https://www.newgrounds.com/portal/view/703358