This was actually fairly good for a children's film.
Yes, it it was sort of generic and came complete with a cheesy moral at the end, but it was pretty well-animated, the cast was likeable, and the plot got pretty sad/"Gah! That's awful!" for a story aimed at children. It also had a few really cute little touches in the characters, like when Wataru crossed the street, his gait was weird because he was taking care to only step on the white bars, and how his mother flipped over the divorce papers when he walked in the room. Also, the animals in the fantasy realm were adorable! There were these things called Corkscrew Wolves (or something like that), that mostly looked like some sort of canine, but mixed with a SAND WORM! So cool!
Not the best movie I've ever seen (by quite a margin), but it was cute enough, and it's not like I had anything better to do at the time.