There are various ways to make you afraid or unsettled. And in my opinion the most effective is fear of unknown.
This world, your imagination and good ambient sound ....
You have nice recipe for good horror game.
What i disliked is the lighting, its way too bright.
Plus the weapons.... i think they should have gone with Soma/Amnesia style without weapons. Or make them really unique and not just reskinned pistol and shotgun.
You know like the big gun with a shot extending its part and biting / eating the enemy. Small gun ...i don’t know ... perhaps lunging itself as a parasite and digging inside the enemy or just immobilising them. Ok these are just silly examples, but you get the point what i mean. The pistol and shotgun are simply immersion braking.