It's a nice watch. Until you think a little bit harder.
It looks good, the pacing is solid with ups and downs as one would expect them, and they do generally make sense. It could have sounded a bit better, considering it's music-related. The message overall is good, "don't let your inner child die" and "don't presume things", at least if I am interpreting it correctly at all. But the living ghost thing did not make much sense, and overall felt kind of shallow.
He was not really needed. In fact, one could argue, that he did not even do that much for other characters through out the movie. Interactions with him were mostly for the sake of moving the plot, and not for the sake of realizations being forced onto people, so that they grow. Especially the one closer to the ending with the cords breaking - it did not really mean much aside being a visual representation of a "turning point", which was not really needed, since the cogs were already turning.
I think, if they went for a TV show, instead of a movie, made music a bit more of a character (perhaps similar to Girls Band Cry, so that it's integral, but not overshadowing interactions) and went for concept closer to Anohana, so that the "ghost" is more involved with people - that would have potential to be a great movie and a tearjerker. As is... Not bad, has some good moments, but overall kind of forgettable.
