It's difficult to quantify the quirky existential animated comedy Western that is director Gore Verbinski's Rango. The first re-teaming of Verbinski and actor Johnny Depp since the popular and profitable Pirates of the Caribbean: At World's End, Rango follows the adventures of a lonely chameleon who accidentally becomes the sheriff of a doomed desert town called Dirt.

In the role of the title lizard, Depp sounds like he's having a lot of fun, and his character's introduction at the start of the film is reminiscent of the same kind of rapid-fire gleeful abandon that Robin Williams imbued the Genie with in Aladdin. However, Rango isn't a Disney film. In fact, the character designs for some of Dirt's citizens are so repulsive it would be hard to believe the filmmakers had any merchandising plans. What child in her right mind would ask for a lunchbox emblazoned with the likenesses of a grizzled old prospector mouse named Spoons or a creepy, toothless mole named Balthazar?

Character design aside, Rango is eye-popping. Explosions, gunfights and grand posse chases are ferociously animated at a breakneck pace. Likewise, the grand, static overhead shots of the town and the expansive desert vistas beyond are like something out of a modern-day Sergio Leone film.

And speaking of Leone, there are several subtle tributes to classic Westerns throughout this imaginative tale, written by John Logan (Sweeney Todd, The Aviator). Rattlesnake Jake (Bill Nighy) feels like the reptilian version of Henry Fonda's cold-blooded gunslinger from Once Upon a Time in the West, and Rango's spiritual journey of re-invention set against the backdrop of a dusty desert landscape invokes the spirit of existential Westerns from the '60s and '70s, like El Topo and Django.

Four very smooth mariachi-playing owls contribute a great deal to the Hans Zimmer soundtrack. Doubling as both Greek chorus and musicians, these earnest performers narrate Rango's epic quest and provide some of the movie's biggest laughs. Music cues from classic films like The Magnificent Seven will also please fans of the genre, and a judicious use of "Flight of the Valkyries," puts a humorous twist on an iconic scene from Apocalypse Now.

But despite all of its flashy action sequences and the humorous heavy-lifting of its star, the film still holds the viewer at arm's length. The romance between Rango and his shrill ladylove Beans (Isla Fisher) never fully materializes as the heart of the film. In fact, the soul of the movie comes less from the protagonist and his female co-star and more from characters like the enigmatic Spirit of the West (Timothy Olyphant doing a stellar Clint Eastwood impression) and Roadkill (Alfred Molina), a wise old armadillo and seeker of spiritual knowledge.

Ultimately, although Rango does a lot of things very well, it's just good and not great. Western enthusiasts and Johnny Depp fans should enjoy it on the big screen, but everyone else would do well to wait for the Blu-ray or DVD.

Rango opens in theaters today.