Have to agree with the guy below or next page. Last level is overkill, because you go from easy to a little resistance to hard. The difficulty curve is a little weird on the last level. But the game mechanics are cool, I like the game a lot and the upgrade system is clear and easy to understand. Give a little more backstory and boss fights and maybe more weapon arsenal like lasers and photon cannons and such, and you have an awesome game. Good job overall, can't complain.