Sadly I think the game in its current stage is impossible, with two machine guns at the start you can't even pass the first wave, and I dont seem to earn any coins.
I also must say the the interpretation of the theme is a bit for a stretch, for a 48 hour project this was very ambitious though and it's cool to see that you put together something functional. With another day of dev this could've been one of those flash games you played in primary school as a kid. Good work!