I enjoyed the story and watched it through to the end. Unfortunately, the finer details of this bittersweet drama dragged down on the quality of the story overall.
My chief complaint is that most of the emotional dialog was dreamed up without the benefit of understanding how both young and older children realistically process the world and deal with family abuse, trauma, friendships, rivalries and romance. Most of the inner dialog of Kousei and his rival pianists made no sense and was downright implausible in light of similar real situations that I recall from my own childhood and that of my 6 children's childhood. In short, the screenplay was very poor in this regard. Although the careful character development helped keep the story from completely falling apart, overall, it was a disappointing watch for me.