Track 1: Definitely an unsettling first track, it gets the eerie mood of the game across very effectively. I do feel like the piano became a bit redundant after a while (it also felt out of place without any reverb in this mix.) Also, repetition of the same four chords over and over should be avoided when possible, as it takes away from the motion and intensity of a track.
Track 2: I am so delighted by this beautiful guitar playing-- is this you playing live? Quite a lovely track, one of my favorites. This piano-guitar texture is one I would like to explore myself.
Track 3: Another nicely done track!
Track 4: really cool final boss theme and an awesome tonal shift-- could definitely feel the intensity mounting. Loved each of the various sections of this piece-- it kept changing, and kept me listening.
Good job on this soundtrack, and keep writing!