I really liked this song, you're a talented composer. In my ears the song was reminiscent of Beethoven's Moonlight Sonata. After listening to it all I could think was, 'man, I have to write a nocturne'.
It is hard to be critical of this song as it was done beautifully. The only thing I would suggest is perhaps a more aggressive attack somewhere, a burst of ferocity that is then diminished into the bliss of the song's soft theme-- to add more diversity. Of course, there's no right or wrong here, it's preferential. You've inspired me to work harder as a musician, good work.