I like the game,
I think it needs some minor improvements but it's fun to play.
It definitely needs an in-game how-to-play or objective so players don't have to pause go read the description and come back.
maybe have it so that you can move and fire at the same time. Also at the shop maybe add an indication to which attack you're currently selecting along with how much it costs. For the mini-game to use the attack it's nice but at first, I didn't know what it meant, it took me two tries to do it and figure out what I'm supposed to do.
The art is really cool and the idea has a potential, good job!