A simple plot with a hoky sledgehammer moral and beyond-gratuitous gadget effects. The themes (family, communication, self-esteem) are good. Everything else detracts. C+.
And here's a note, which is related, but not really a review of the movie: In my view, one of the things that makes great children's entertainment really great is that it talks with the kids, rather than talking down to them. Good children's entertainment speaks in the language of kids, rather than the language of adults-trying-to-communicate-with kids. The best example of this is Mr. Rogers: he seemed ridiculous to many adulds, but fundamentally, he spoke to kids in their own language. Sesame Street, and Winnie the Pooh, do the same: They approach things the way kids do. Movies like Spy Kids seem to me to be made by adults who assume that if you just cram something full of silliness, kids will love it. And maybe they will. After all, lots of kids love fart jokes. (Which, I note, are at least as abundant in a lot of distinctly grown-up comedies as well). But when we do that, aren't we losing something? Aren't we bringing kids down to the vapid level we expect them to be at? Isn't kid silliness different from adult silliness?