The buildup is really good. Once you really get into the song it kicks off good. The song is really clean and diverse as far as the way you apply each instrument. I noticed nothing negative about the mastering or overall structure of this track. Well done there!
The only thing that disappointed me was the lack of melody. What you did use was really appealing, I really like the melancholy feel. I just expected a little more melodic diversity for a song that's almost five minutes long. Don't get me wrong, once you write something that hits off really good and you really like the sound, it can be difficult to explore outside that melody... but I would recommend a deeper look into the scale you used. There's a lot of melodic potential for this song. I think it's good now, but it could be better.
Oh, and I scouted you because you deserve to be in the portal. :D