This game is super cool.
The music is catchy, the gunplay is engaging, the theme implementation is fine and you've got a bunch of different weapons, levels and very nice bullet patterns there. The game is challenging, I like that, I could not beat the 0/18 level just after the second shop so far.
I have a lot of fun playing this.
You should add a cover image so that more people play the game, just copy one of the screenshots there or something.