The music in this game is awesome! I really love the track for the second level and the unlocked level with the weird sinewave boss, the tracks for those were especially epic, I wanted to keep doing those levels just to here it honestly.
I was having trouble before realizing that I could switch weapons (which was my fault I didn't properly read the controls!) but then realized that the hexagon shield weapon was awesome and can even deflect projectiles.
Did all the levels using that weapon, only managed to do the first boss with the inital one. Nice work on this!