Pretty nice game, congrats! I like how you reinforced your take on the theme giving mostly only the bullets you need to beat the game (that forced me to go back and reuse them). 

It was actually pretty cool!

I was worried about the projectiles disappearing and not having enough to get rid of the zombies but there was just what we needed.

I did try to kinda speed run the game and when I had all of the zombies following me in the last room I decimated them! ^^ And yes I tried going in the acid trap even though it seemed obvious (seeing the depth of it) there was no way to go back)  but I think you should have done something with the doors opening: Since you can technically speed run the game easily, maybe opening the door when all the enemies in the room die would've avoid what I did.

Since you are on Unity you can do that by: Having a game object representing the group of enemies and send an event to check if at least one enemy (children of this game object) remains in the group. (the parent game object) There are other ways to do it of course and maybe it's obvious to you but I'm throwing it there if it can help.

[SPOILER ALERT!]

I have found the end of the level pretty obvious since I thought about rigid bodies but I have no idea if it would be obvious for someone who didn't use a game engine (aka a "normal" player) without any help.

[END OF SPOILER ALERT]

I wrote a lot to explain only 2 minor issues really but it didn't break the fun at all in my experience! :)

Other than that the game was very easy to pickup if you played FPSs before, the AI was simple (zombies! Did you use a navmesh by the way?) and it was working correctly, the theme was well used and the light effect on the projectiles added a nice little touch to this kind of dark world, the zombies were funny to look at which also added some personality to the game and the end added a mini puzzle (survival fps horror + puzzle? :P ) to use your brain before the one you are supposed to retrieve.

So in the end, I had a lot of fun playing it!

Was realy esasy to jumpt in and start to play. And 

we actually have the same concept :D in our game we have to pick up bullets too.

Fun game! I wish attack speed was a lil bit faster tho.

I liked zombie models :D I think theme was pretty well involved into a game. I was kind of confused what to do with brain after I found it and why it levitated X D

This is a fun game, couldn't get the controls to work at first but that's probably just input lag. Had fun playing, though!

Fun short game.

Just as a feedback, the door opening sound is WAY louder than any other sound.

Love the game, great job

Loved the reusable bullet mechanic! Was a really cool spin on the theme for a shooter game