Crazy idea, great game. What's really interesting is that you don't want the bullets to be dangerous for you so you pick least effective upgrades but then more enemies comes up and you regret that idea. The online scoreboard is insanely cool, absolute quality
Glad you liked it! Some things in the game are not quite intuitive, so yes, would be nice to have some kind of hint. The sounds were added in a hurry, probably will polish the game after vote