Nice game, I got to level 3 at best try. I think you could've made the aiming a bit better, maybe by adding power-ups like a pointer that would tell you where the bullet will exactly go, if you know what I mean. Otherwise, great job!
There is a laser pointer option that will help you aim in the options menu! (Escape, or settings in the main menu). If I had the chance now, I would've turned it on by default.
