Rodriguez kinda makes it easy for Depp, giving his inadvertent star a cluttered mess amidst which to be totally centered and in control. You have to admire Rodriguez for deciding be a one-man show behind the camera -- scoring, shooting, cutting (as he delightfully terms some of his jobs in the opening credits), writing, producing, directing -- and keeping his films under his own flag and making them in the garage like filmmaking's a hobby he pours painstaking devotion and obsessive love into. Even when he turns out a complete disaster -- like the mind-bogglingly Ed Woods-esque Spy Kids 3-D: Game Over -- there's a ragged energy to his films, a singlemindedness that's the antithesis of the corporate filmmaking that dominates Hollywood. Rodriguez's movies will never be mistaken for anyone else's.

And yet that singlemindedness does come with a downside: There's no one, apparently, looking over Rodriguez's shoulder and saying, "Um, you know, that's not quite working, and this needs a little more focus." It didn't matter so much with El Mariachi, his breakthrough film that he made for like $1.98 -- he didn't have the financial wherewithal to go crazy with stunts and stars and stuff blowin' up real good, and that film is a little masterpiece of minimalist visual storytelling. And while Once Upon a Time in Mexico is a stronger film than Desperado, it's still chock-a-block with too many characters bouncing off one another, still lacking a narrative cohesion. Rodriguez is bursting for fabulous ideas, and he's so madly in love with all of them that he can't bear to kill any of them.

It seemed to make a sort of sense at the time, sitting there in the multiplex with all the culty Desperado fans hooting and cheering around me, but damned if I can unravel Mexico now. El Mariachi (Banderas: The 13th Warrior, The Mask of Zorro) is back, of course, the reluctant gunslinger who carries his weapons in his guitar case and is still out for vengeance against the Bad Men who forced him into this line of work. At least I think it's the same group of interconnected Bad Men here -- I could be wrong. Somebody is plotting a coup against the president of Mexico (Pedro Armendariz), though now I can't remember if it was military strongman Marquez (Gerardo Vigil) or drug lord Barillo (Willem Dafoe: Finding Nemo, Spider-Man) or maybe whether they were in it together. But it's a reason for Rodriguez to use all the visual cues of military strongmen -- the fatigues, the jeeps, the bandoleers -- of drug lords -- the white suits, the facial reconstruction plastic surgery -- and grotesque Day of the Dead parades and dusty little towns and big old churches and old ladies with rosary beads. Throw in a bit of patriotism -- El Mariachi declares himself a "son of Mexico," motivating him beyond mere revenge -- and you have a dreamscape of a nation, a mythmaking on the order of the cowboy westerns of old. It may not make a whole lot of sense, but there is something stirring here.

But for all the charismatic personalities onscreen here, no one keeps his or her head above Rodriguez's flood of chaotic reverie... except Depp. Johnny Depp (Pirates of the Caribbean: The Curse of the Black Pearl, From Hell), the sly bastard, exudes a gunslinger glee, a celebratory disdain for morality and basic human decency that animates his rogue and probably insane CIA agent in a way that's a little bit terrifying -- his emotional conviction is such that you almost have to believe he's not really acting -- and a whole lot wonderful. It's hardly fair to the rest of the very talented cast, but Depp heedlessly puts his fellow cast members to shame -- it's like we can see that they're merely performing while he is being. Depp is the center of gravity around which the entire film revolves, and the black hole that sucks the audience's entire attention -- when he's onscreen, he's all you're watching, and when he isn't, you're just waiting for him to come back. That's not a bad thing, though you have to take pity on poor Banderas and Hayek and everyone else -- it's a thing that leaves you in awe of Depp.

And it's a thing that makes you suspect that Once Upon a Time in Mexico would have been ultimately forgettable without him. Instead, it's compulsively watchable... but mostly cuz you can't take your eyes off Johnny Depp.