It was very good, but I felt that it was a little disjointed. It seems like you had 2-3 ideas for a song and couldn't decide which one to use, so you stuck all of them into one piece. I would sacrifice length and put each main theme into their own piece. It would give you a chance to develop each one more fully.
Also, it seemed to be missing a musical element. I listened to it a few times and realized that you are missing a lot of the lower tones. The low, sustained notes that bring the whole piece together. Incorporating a climbing or opposing bass line to the melody would add that extra level of depth. The piano section about 2:40 in was a good start.
Overall I really like it. It shows that you put a lot of work into it. Well done.