Disney ’s "Bolt” is the studio’s best non- Pixar computer-generated cartoon to date, a shaggy-dog tale that owes as much to "The Truman Show” as it does to "Lassie Come Home.” Young kids might not get the film’s meta layers, but characters are funny and cuddly enough that they just might not care.

As it opens, Bolt (voiced by John Travolta ) is a puppy getting picke...