One of the most depressing movies I have ever seen, if not the most depressing. I loved the way the movie was made, from the drawing of the characters to the way they expressed stuff, even for an animation - very profound. The saddest thing I have ever seen I think until now was the part that shows why the movie is called the way it is.
It's hauntingly beautiful and I don't think I have ever described an animated movie in such words.