It ended up being Miyazaki's son's first movie, and is a mashup of the entire series and some other stuff. Famous for this tidbit (quoted from Wiki):

During a private screening prior to the film's release, Gorō's father, Hayao, was asked what he thought of the film. He said, "I was looking at my kid. He's not an adult yet. That is all."

Le Guin was also not a fan, so....