Loved the Idea and the use of the theme, striving to balance out collecting score and having enough ammo was engaging.
I think the game starts out a little too slow, the time gap between waves creates big windows with nothing to really do, and the start waves themselves are too easy.
the most fun I had with the game was at the later levels, when I almost ran out of ammo and needed to maneuver myself carefully and think about what type of ammo to spend. I also loved the sound of collecting coins. overall I think with some polishing and mechanical tweeking, this game could become great!