Leaping lizards! We all know that Johnny Depp is a chameleon. He plays one, or more precisely, voices him, in Rango.

This off-center animation from Gore Verbinski (Depp's director in the Pirates of the Caribbean series) opens with a quartet of owls in mariachi garb singing the legend of the lizard. They pop up at regular intervals to musically comment on the chameleon's exploits in the Southwest, where the land is bone dry and the wit even more so.

Rango is best enjoyed by those over 10 who have an idea of what "existential" means and can appreciate a surreal mashup of Chinatown, Gladiator, High Noon, and The Good, the Bad and the Ugly.

You know those animated films that have bits that the parents will enjoy? Rango is mostly those bits. The film is for movie geeks and Depp fans tickled to see the gonzo actor role-play around. (Before he dons his chaps, the chameleon sports a Hawaiian shirt and has the bad-boy attitude of the late iconoclast and journalist Hunter S. Thompson.)

When first we meet the lizard he is improvising a scene with some interesting props: the torso of a Barbie doll, a toy fish, a cocktail umbrella, and one of those plastic spears used to deliver olives to the martini glass. Turns out he is a pet in a glass terrarium in the backseat of a car that gets sideswiped. Miraculously, he avoids becoming roadkill.

A philosophical armadillo (Albert Molina) directs the modern-day chameleon to the dusty 19th-century town of Dirt, populated by thirsty reptiles, parched rodents, and the Mayor (Ned Beatty), a turtle who oozes sinister charm. Like Noah Cross, the John Huston character in Chinatown, the Mayor is busy diverting the water supply and keeping the townsfolk dependent and desperate. (Interestingly, Chinatown was likewise the basis of Who Framed Roger Rabbit?)

Enter Rango, playing the part of the highfalutin, rootin'-tootin' cowboy. The townspeople recruit him to be Dirt's next sheriff, a job whose duration typically is measured in hours rather than years. He befriends Bean (Isla Fisher), a red-ringleted reptile, and with her organizes a posse to rehydrate Dirt.

While the photorealistic animation (from Industrial Light and Magic) is exaggeratedly sharp (you can count the scales on Rango's E.T.-like face and the feathers on the singing owls), there is almost too much visual detail in Verbinski's busy movie. I was on optic overload, which has the effect of upstaging the narrative.

Still, I enjoyed many of the visual touches, especially the reptiles saddling up roadrunners and riding them through canyons.

Yet while I laughed myself silly at the myriad movie references (especially one involving water beetles transporting the body of the fallen, suggestive of the floating Russell Crowe at the end of Gladiator), are they too inside-baseball for younger viewers?EndText

Contact movie critic Carrie Rickey at 215-854-5402 or crickey@phillynews.com. Read her blog, "Flickgrrl," http://www.philly.com/philly/blogs/flickgrrl/