This is a really nice and creative game! I really enjoyed it. At first I was a little confused that the 'bullets' I shot did not hurt the enemies. Then I realized that I was actually shooting guns, which were in turn making the bullets, and I thought 'that is really cool and chaotic'. You kind of make your own bullet-hell game, which is really interesting.
Sometimes a gun would shoot if it were right in front of me. This felt a bit unfair sometimes, especially when I just created it. Perhaps it would feel better if guns only shoot if they are a certain distance away from the player? Maybe this is not what you were going for though :)
The art was really nice as well. Are these just simple shapes with some pixel shader on top? Or how did you do this? Anyway it works really well :D I echo the others that some music would be amazing. Some extra game feel would also help a lot I think.
Great submission! I really enjoyed this one :D