I'm going to go easy on this one. Miyazaki Goro, Hayao's son, made this movie. He excels in static forms of art (architecture).
So first things first: the author of the original story passed away before finishing. No one knows what happens next. The staff dealing with this movie were young animators - which explains why there are lighting issues. The movement is okayish, sometimes dull, almost unfinished. The storyboard needs more work and is tedious at times. I'd give this a 4/10, but considering it can be a good watch for little kids, I'm giving two extra points.
It's a movie you'd put on for kids you're babysitting. Maybe to make fun of Earwig's ponytails. Or that disgusting shepherd's pie.