B+ | Enhance the creepy.
Reminds me of walking through a living forest, but with your objective in sight. The lack of drums threw me off, I like snares and deep drum beats in ambiance. Not something I would listen to outside of a game, but would definitely fit into one.
I would suggest less repetition, and more creepy noises. For example a small sound that reminds the listener of a dieing, stalking, or scurrying animal.
Your music, your style. Good job!