I enjoyed playing with it for a short while but there needs to be a goal or something to play towards to make me play for longer. I collected the things but I couldn't use them and didn't know what to do with them.
There are some bugs that if you could fix would make the game much better. Also some improvement tips:
Sprite layering order has some problems. The player will often go under objects that he is not supposed to.
Player can't move in all diagonal directions.
Zombies spawn on top of the player or very close to the player.
Zombies can get stuck on invisible things. Maybe on the ground, I don't know but sometimes they get stuck.
Player can leave the play area and the camera doesn't follow. A simple invisible wall could do the trick.
Player turns too slow. And since you don't shoot where your mouse is but where the player is turned this makes aiming very hard.
Radio doesn't work.
Instead of leaving with a button if you could leave through the door that wouldn't be this weird.
Zombies spawn only in a corner of the map and the rest of the map is empty. Also zombies are no challange to dodge. Maybe make them faster.
If I could shoot with holding the mouse button down that would be better.
Anyways, keep improving! It doesn't need a lot to be a great gamejam game.