Written in a week and shot on the cheap, with Robert Rodriguez doing pretty much everything but the catering, "Once Upon a Time in Mexico" is the second sequel/remake of the Texan director's low-budget killer hit "El Mariachi".

Antonio Banderas reprises his "Desperado" role as the gunslinging troubadour, hired by Johnny Depp's rogue CIA agent to off the general tapped by Willem Dafoe's drug dealer to undertake a coup d'etat.

Unclear? Get used to it, as a sprawling narrative is rammed into 102 incoherent minutes. Other bit players include Rubén Blades' FBI retiree, Eva Mendes' cop, and Salma Hayek in frenetic flashback.

"Spy Kids" aside, Rodriguez's best features are "The Faculty" and (the first half of) "From Dusk Till Dawn". It's telling that he didn't write either of them. For while his emphasis on action can be enthusing, here it's done at the expense of all sense.

And the 'spectacular' set-pieces are largely as flimsy as the story, with great ideas tossed aside half-exploited (such as Banderas and Hayek's chained descent, swinging monkey-style, from a building) and actors underused (Banderas takes a backseat, Dafoe is utterly wasted).

The saving grace is Depp as the louche loner, whose off-kilter sensibilities are evident in his character's clothing (one t-shirt is emblazoned CIA, another bears the slogan "I'm with stupid" and has an arrow pointing to his crotch). He also has the best line, snarled at Danny Trejo's stone-faced hood: "Are you a Mexican or a Mexican't?"

Pity that such wit isn't evident elsewhere. "Once Upon..." isn't unwatchable but it feels half-formed, a shoddy Sergio Leone 'tribute' filmed from a first draft by a director who lacks the discipline to match his talent. The credits proclaim this to be "A Robert Rodriguez flick". It's about time he made a film.