I liked the visuals (especially the fire and the explosion effects), the music was good but a little loud maybe. SFX was good
I agree with the other comments, I think having a "coin pickup radius" upgrade and cranking up the difficulty to accommodate, would really help this game to feel more smooth and definitely more survivors-like if that's what you're going for. I also think there is a lot of potential for varied enemy types, like one who stands still for a few seconds in the back and then shoots from long range (but has very low health), or one that heals all his allies in a given radius so you have to take him out first, etc.
Overall this is a cool game and a great job for your first game jam ever, nice!