Kind of hard to put it in actual words despite siting there in awe. It really has a mesmerizing hauntingly beautiful nature. The ambiance and soundscape you’re creating in the first two minutes are very believable and create a nice entrance to the main piece. Also the sparse arrangement works very well with the set up atmosphere without feeling hollow or like it is missing something. The mix is done competently well and amplifies the compositional tone well enough. Surely there might be point of improvement, but these points would be minor things since there aren’t any elements that hinder the listening experience in any way.
While this point is not part of my critique and rating. I’d recommend looking into automating panning to create more movement in the ambiance. You’ve nailed each scene by itself perfectly but (this is hardcore nitpicking and nerding out) it feels like moving from picture to picture and not also wandering inside it. So my tip would be to consider how the sound might change while walking thru the scenes. Are things moving from left to right or center? Or are things fading in and out? I think nailing this would even more mesmerize the listener in even more emersion and elevate this strong submission even more.