I love this main mechanic. Being unsure as you fire at where the zombie was until you get a confirmed kill is a great feeling, and turning the torch back on to see one right behind you... The music and visuals really up the experience.
However, I think that the length of this game overstays it's welcome somewhat: the main mechanic is revealed at the start of the game, but isn't really varied, explored, or remixed in any way throughout the levels. It would have been served just as well by one single level. There's also the problem of repetitive stress injury, spamming LMB wasn't very friendly to my fingerbones.
This game dazzled me to begin with, but struggled to hold my attention. Another day of work to add something new would do wonders. Great job!