Hey dude, you've constructed a great atmosphere, here. Kudos on your sound design--I especially like your use of deep ambience, and those zombie monster things sound genuinely alarming!
Any plans for music? In a lot of ways with the horror genre, less is more, but it can be beneficial to have some select, subtle music happening here and there. As a sound designer and composer I am especially interested in providing a soundtrack to a game like this. If you were interested, I'd be willing to compose for you, all pro bono.
Otherwise, keep up the good work! I'm excited to play this when it comes out!