I have watched this movie 2 times now and everytime i see it makes me feel pathetic and that my i'm going to die sad.
But besides that the story is pretty good. The art Holy Cow, "amazing" it's still a short word to describe how the background art is. And sure, it sacrifices a little of character designs and "solid" strokes to make it more complementary to the ambient, but it's still too good for a movie that lasts for more than 1 hour.
It's a movie that you are going to appreciate, but it also a movie that will make you sad for various reason (probably).