While this Studio Ghibli film has echos of Spirited Away, it has neither the richness of animation nor the depth of story to compare. That doesn’t make it bad, but it does shift the audience to be decidedly younger. And, for a younger audience, it is likely quite magical and engaging; especially for girls since the main character is a young girl who gets to save the day.
Director and co-writer Hiromasa Yonebayashi (The Secret World of Arrietty) knows the language of children, their sense of wonder, and their unrelenting drive. He captures that aspect well. But without more meat, like his previous When Marnie Was There, it is really just a pleasant distraction and long-form cartoon rather than a movie.
If you like Ghibli’s catalog, particularly the stories intended for their newest enthusiasts in your household, this is a great choice. It has just enough adventure and danger to keep it feeling exciting for them, but nothing permanently bad happens, making it safe. For adults, it will depend on your tolerance for the sillier aspects and overly-simplified plot in exchange for some of the more creative efforts.