Story: 9/10
One of the genre tags for this movie is "beautiful", and I completely agree with that. The reason why this movie is so beautiful is because of the simplicity of the storyline. There are no fancy mechas or grandiose plots; instead, you have very realistic characters facing very down-to-earth conflicts.
Art: 10/10
Giving anything less than a 10 in this category would be an abomination. The animation and art are so good that it sometimes felt that I wasn't even watching an animated movie. This movie is definitely worth watching just for the amazing art.
Sound: 10/10
Beautiful piano melodies are intricately weaved into this movie to effectively portray whatever mood is needed, be it melancholy, nostalgia, or rejoice. It is also worth noting that even though most of the OSTs are variations of the same melodies, at no point did the music feel repetitious.
Character: 9/10
The fact that the characters are so down-to-earth makes it much easier for viewers to empathize with them. Character development is minimal save for the last chapter of the movie, but this does not take away anything from the movie.
Enjoyment: 10/10
Personally I enjoyed this movie a lot. Beware that save the last chapter, this movie is rather slow-paced in the beginning, so action-junkies may wish to stay away.
Overall: 9/10
A brilliantly told story of an unattainable love. If you prefer slice-of-life and romance genres, then there should be no reason for you to not watch this.
