cool game, with a little more of work, adding weapons and an upgrade system well be awesome

Things I would change:

The player should move faster
The zombies should all despawn when the player dies
The sound of the character getting hit should not overlap (it gets really loud if you stay in the top right corner for too long)

Bugs I noticed:

you can still shoot while reloading; you can spam R and hold Mouse 1 to shoot an endless stream of bullets
When out of bullets and holding Mouse 1, the gun will still experience "recoil" and jitter back and forth as if it was still firing

It was a fun little time waster though, and I thought it was fun.

the controls are strange, and the mechanics are lacking.

I don't know what you were reaching for when uploading this to the site. I mean, this isn't something anybody would play from the current state it's at.
I'll give you some pluses for the design though (if that's what you're looking for). The player and enemy models and animations look great, if you made them then give yourself a pat on the back.
If you want criticism, then fix the poor sound quality for the walking (background noise) and add some interesting game elements, fix the zombie AI so it doesn't walk a straight path.

So far the game looks like the arcade game Asteroids but with 0 thought put into it. I think this project would be sick if you actually expand on the issues and later upload the full project, not a beta with an open plain to walk around. :)

You said it yourself. It's just a beta, even if I think it has some work before it's a proper beta.

In it's current state it's not fun to play. The game only has the basic mechanics. That's why I only give it one star.