Right, then!
Unfortunately, my technical knowledge of music is very restricted, so my descriptions will be rather.. unprofessional.
It's truly a pretty song, it gradually gets better, too.
My points of criticism are that it could, mostly in the beginning, use some more flow... there are many instants in which you have a series of notes, a little break, and then another single note, whatever you may call that.. it's even in the leitmotif from what I can see.. I think using that technique too often through a song makes it become a little stale and takes away from the tempo, although that might be intended, I don't know. If possible, I'd try to bring more flow into such instances, though I admit I don't know how much is possible with a single piano...
Second point is that I kind of miss a curve of "suspense" ( emotion in this case, rather ). It starts out rather.. calm and quiet, then turns more emotional, but it kind of rests on the same level of emotionality for a while from what I felt...
And finally, a suggestion. The strong emotion in the later part of the song was expressed mostly by powerful notes ( or several notes at the same time? I'm not sure ). Another pretty good means of making music more powerful is to give it more depth by employing high as well as low notes. The contrast of the bass makes the higher notes sound even stronger.

Of course, these are only suggestions and ideas that I would have used, I don't know what your idea for the song was and what you want to express, soooo... yeah.