It wouldn’t really be that interesting to be inside Robert Rodriguez’s head at around 2 a.m., just when he’s dreaming up his next set of fever-pitch ideas. With most directors, it would be the exact opposite. But not all directors uncork their imaginations onscreen the way Rodriguez does; as an audience, we get to see every little ounce of creativity he’s got.

The original Spy Kids was a giddy delight, a well-rounded film that stressed the narrative power of a family bond and the economical power of a dollar. Rodriguez made that film for $35 million – paltry by Hollywood standards. Rodriguez knows that if it ain’t broke, you don’t fix it. Thus, he’s kept his budget corralled and his themes stronger than ever in Spy Kids 2: The Island of Lost Dreams, which is not as zippy as its predecessor, but is still a worthy follow-up.

The plot in Spy Kids 2 is merely a hook on which to hang Rodriguez’s visuals and themes. Carmen and Juni Cortez (Alexa Vega and Daryl Sabara) have returned, only this time as part of an entire team of Spy Kids assembled in the wake of their initial success. When a gadget called the Transmooker (which shuts down all power in the area when turned on) is mysteriously stolen, only the original Spy Kids can bring it back.

Their quest leads them to an island that’s unable to be detected by traditional satellites, on which resides Romero (Steve Buscemi), an exiled genetic scientist who lives in fear of the animals with altered DNA that he has created. After contact with Carmen and Juni is lost, their spy-happy parents (Antonio Banderas and Carla Gugino) go looking for them. But they’re not the only ones on the trail. The kids’ grandparents also end up on the ride, as well as a pair of rival Spy Kids who may or may not be allies.

This film is a whirligig of invention from the opening sequence, which features an amusement park attraction where the riders are literally juggled in the air. From there, it just gets increasingly fascinating. A group of henchmen with magnets on their helmets get sucked up one by one to their getaway ship. An electronic frog leaps its way across the Spy Kids office in order to provide intelligence for Carmen and Juni.

We’re bombarded with nifty gadgets and more gadgets to top those nifty gadgets. But Rodriguez doesn’t merely rest on throwing a lot of cool technology in our faces. For a great portion of the movie, Carmen and Juni are in situations where their gadgets don’t work. And there are several big laughs in the notion of a “spy watch” that does anything but tell time. The humor also extends to sight gags, which play wonderfully on the notion of compound animals such as bullfrogs.

If anything drags Spy Kids 2 below the level of its source tale, it’s the film’s midsection. The first and third acts are anchored by Rodriguez’s desire to dazzle, while the second act is mostly exposition and weak comedic banter between the parents and grandparents. Rodriguez is much better at showcasing the family’s genuine warmth and dependence on each other to succeed, as he does in the final scenes of the film. And his brilliant homage to Ray Harryhausen’s stop-motion visual effects of the 1960s gives the climax an action jolt it needs.

It would be good enough that the movie boasts technical proficiency and a sound narrative. But it’s clear that Rodriguez is having fun, and is passionate about the craft he’s chosen. After all, this is a guy who subjected himself to experimental drug tests to raise money for his first film, El Mariachi. The only thing we don’t know after watching Spy Kids 2 is whether Rodriguez’s constantly churning brain leaves him any time to sleep at night.