I really enjoyed this piece, it had a really beautiful atmosphere throughout and all your musical ideas are laid out clearly.
Your score looks very nice (a big issue for me, score presentation) and your musical grammar is good (such as writing a G# after the A flat in bar 27 which makes it correct intervallically and harmonically) I have seen many scores where basic musical notation is so poor that it puts me off even listening to it, but I am very strict
The piano writing reminds me of Arvo Part in his simplicity of using arpeggios, and the use of the low register open 5ths and octaves it really lovely.
I think, more interaction between the parts would work better perhaps some supporting harmony lines or even independent counter point. The musical material is relatively simple, so you could probably decorate it in the part that is not playing it.
You do introduce 2 part writing a little later which works nicely, but maybe a little bit more? I can understand how you may not want to over clutter the texture so that makes sense.
As has been said before, the ending is a little sudden, maybe another 2 bars leading into that would be more effective but it is your personal choice, perhaps it could lead in attacca to another movement?
A great piece though and you should definitely put more of your stuff up here! That's an order!
