Really, really rich soundscapes you got here, I love all the textures and variety you got for the ambience, really threads it all together well. I'd say the fourth track is my favourite of the bunch because I felt it progressed a bit more musically than the others and had a bit more to it.
This track, I'd say, works perfectly for some kind of game OST. The first three tracks really sound to me like just plain ambient background music for different areas/scenes; they each had a different feel: enchanting/mystique, the uncovering of something, very tense/sinister. And I think that this track, overall conveys a story very well, and immerses you into the space that you've crafted musically. (I will note I think you crossed over the max runtime a smidge, but it's fine)
Really enjoyed listening to this track! Great work!