The premise is interesting and the game is pretty polished, but it needs some changes to make it more fun.
I would love if the rolling of the dice felt more important. Right now it feels like a very slow reload witch isn't that rewarding. Maybe if you could get some powerups from a dice that make you faster, kill zombies you touch, make your bullets explode etc. witch would make killing the zombies satisfying. I get you were going for a slow creepy atmosphere but the most efficient tactic seems to be walking in a circle and shooting behind you so a faster arcady style might make it more interesting .
Another way you could've gone is making the zombies rare but more powerful and that you are forced to roam around in the darkness to find something important (eg. the dice for more a new weapon, health or sth like that)
I'm just writing down the ideas I have to hopefully help you if you decide to further develop the game, I hope you don't mind :D