I remember reading the manga and found the story quite touching and beautiful.
I think the movie suffers from the editing and pacing to the point that I don't want to recommend it at all. I remember actually pausing several times to see how much time was remaining until the end because I couldn't believe how it was dragging on. There's several moments where you feel a sense of relief "...Ah, everything will get better now!" and then a twist! things are just as bad as before, or worse! The manga was able to handle these better, but in a single movie, maybe have that happen once, not two, three times!
I also felt almost every actor was too wooden in their performances. Obviously the tone of the movie is very very serious, but having most scenes and characters conversing slowly, and seriously without emotion, usually just standing there (there's almost zero action) made it even harder to get into the story.
Due to these reasons, I found myself no longer caring for the characters to find a resolution, and to just hurry up and get to the ending already. I think sometimes, movies shouldn't try to cram in every plot point from the original source material. Condensing the story would have been more fluid and more impactful. This movie absolutely did not need to be almost 2 and a half hours long!
