I can't imagine how much effort what put into this. The final product, visualy speaking, really is a polished piece of work... Except for some of the animation. This being said. The story feels disjointed and random at parts. I understand it's all metaphorical, and I'm not saying taking this direction is wrong, but the structure of this movie really would have benefited from a little coherence. And what I mean by that is that a scene is shown, exposing a fact, only to be left behind and never referenced again in the movie.
This movie is really, really creative. So much in fact, that I believe it hurts the narrative structure. Too much songs, too much style, too much moods, etc. Now you could say that this is only a matter of taste, and you could be right, but I firmly believe that with this movie going in all sorts of direction, we get this sort of disjointed, weird and random look at this piece. And we loose the emotional attachement we would get otherwise to the character and their struggle.
Also... This is just me, and you can completely ignore this criticism, but the whole boyfriend/girlfriend breakup death thing is a bit cliche. It kinda ruined the ending for me. I'm just saying, there are a hundred ways to make a love story more interesting than this.
So here it is. My point of view. It's not the truth, just what I perceived by watching your movie.