Having proved in last year's delightful live-action adventure ''Spy Kids'' that they have the underage mojo necessary to join the top secret family business, Carmen Cortez (Alexa Vega) and her younger brother, Juni (Daryl Sabara), are officially on the job in Spy Kids 2: The Island of Lost Dreams. Their mission is to save the world, or something like that, and their destination is an appropriately mysterious island, the sanctum of a mad but rather sweet scientist (Steve Buscemi, mad and sweet) and his menagerie of mutant animals.
Nothing, inevitably, matches the surprise charms of the original, when the levelheaded, lively kids, their intricate techno toys, their cool relationship with their parents, and the zesty performances of Antonio Banderas and Carla Gugino as Señor Nick and Señora Nora were discoveries -- un poco James Bond, a bit of ''Mi Familia,'' and a lot of fresh imagination. This time around, the antics are a tad more frantic, and the gizmos work overtime, as if writer-director-producer-editor-cinematographer-production designer-composer/and for all we know caterer Robert Rodriguez felt the hot breath of el diablo on his neck.
On the other hand, the inventiveness is still superior and the network of fiends and family is extended. That a pair of sneaky, less trustworthy junior spies (Matt O'Leary and Emily Osment, sister of Haley Joel) compete with the Cortez sibs for world domination, or something like that, is okay. But the introduction of an older Cortez generation is inspired. Ricardo Montalban and Holland Taylor are so spicy as meddling grandparents (who just happen to be retired pro operatives) that Rodriguez might profitably take a break from the planned ''Spy Kids 3'' and spin the adult Cortez contingent off for their own more sophisticated comedy about intrigue and in-laws.