Paper Monsters

The game looked like fun and definitely seemed like a good shoot em up kind of thing.

I basically found a few things that are strange.
First I believe you are using Unity, in which case, the new version had almost full support for 2D. Not sure why you picked such camera as it was really awkward to deal with.

The aiming felt really clumsy as I had to target using WASD and not the mouse, even though I am using the LMB to fire. I'd prefer to use the mouse for targeting; it made more sense.

The music was OK, but I believe a more upbeat or more fast music would be better as it would get the player all hyped up.

There isn't quite an indication of how I get hit. It is mostly guess work from my end whether I was hit or not (because of the camera angle one thing), there is no feedback when you are hit apart from the sound but visually, nothing happens.

I liked however how the zombie turned red when I hit him.

You have a game that could be something really fun, it just needs some polish and some thought on your design elements and perhaps it could be the next Zombie shoot em up that is a hit :D

Good luck.