Logged in only to tell you this is fantastic. For a prototype, it's got some serious potential!
While there's some problems like hit registration (spamming the attack key whilst being as close as possible to a zombie rather then holding it down and hitting the zombie from far causes the zombies to take approximately 2 to 3 hits in the first swing-animation.). Also, I find the keyboard controls to be a bit awkward, and by that I mean, the enter inspect/activate/pickup key is awkward to reach during gameplay, and with a game like this I don't know if I'd wanna move my hands from the attack/dodge buttons to enter an elevator and activate it, f.e. if I'd be chased and needed to escape via elevator, but still want to keep them back/dodge attacks.
I really like the ambience you pulled off, it actually drew me in for a bit, and the rattling groans put me on the edge of my seat, like some zombie with a chain was gonna drop down on top of me and it would attack me.
I'd definitely support something like this. It's truly got it's charm, and with some work, it could definitely become something pretty cool. You did a great job, dude! Keep it up!