Fairly fun game, some really good design in the first level, but the 2nd level clearly isn't finished, which is still doable. I really dig the music as well, but I'm not sure it really fits with the style of the game visually.
I think to make it a bit more challenging, since it is VERY easy to exploit, is to drastically limit the projectiles' travel distance, since they go on forever until they hit something. Maybe make it only go as far as the camera view limit.
Great job.