Any time a movie has a catastrophic preview at the Cannes Film Festival, there’s a strong chance it will prove worth seeing. So when “Southland Tales,” the second film by “Donnie Darko” creator Richard Kelly, laid an egg at Cannes 2006, all signs were good.

Kelly went back and tinkered with the film, slicing off 20 minutes or so. At long last, the movie is opening. And boy, is it bad.

No summary of the plot is possible, but some kind of apocalypse is about to come down in Los Angeles on July 4, 2008. It’s tied to the disappearance of a movie star (Dwayne “The Rock” Johnson) during a political campaign, just as a weird inventor (Wallace Shawn) has come up with Fluid Karma, a new ocean-based energy source.

Various political agitators are mixed into this stew (many of them played by former “Saturday Night Live” actors), as is a porn star (Sarah Michelle Gellar), whose role is utterly mysterious to me. The key to saving the world, or maybe destroying it, is a cop (Seann William Scott) who has been doubled somehow, so that there are two of him running around. A veteran (Justin Timberlake) of the Iraq war is also here, narrating the film.

You’d think narration would help. If Kelly’s goal was to create a kaleidoscope of modern life, he has succeeded, but most people grow weary looking at a kaleidoscope for 144 minutes.

If Kelly’s surreal explosions were grounded in something authentic and real (the way, for instance, the absurdities of “Dr. Strangelove” are grounded in absolutely authentic policies and technology), it might begin to work. But this is surrealism rooted in surrealism.

In place of the genuinely eerie mysticism of “Donnie Darko,” Kelly goes for overt political posturing here. His thinking on the subject comes across as paranoid and feeble.

That wouldn’t be so bad if the movie at least succeeded at one of its avowed goals: to be funny. I take it Kelly intended something along the lines of Kurt Vonnegut or Stanley Kubrick, but “Cat’s Cradle” and “Dr. Strangelove” had the distinction of being riotously funny. I can think of very little in “Southland Tales” that made me laugh, except Jon Lovitz’s make-up, which makes him look like Ed Wood’s soothsayer, Criswell.

Kelly pulls off a couple of bravura musical sequences, in part thanks to Moby’s musical score, including a dance number in a zeppelin. These are the kinds of thing that make you think, Gee, if I cared at all about what was going on, this would be really cool.

But I didn’t care, and the movie doesn’t work. But, hey, maybe that’s because I didn’t read the graphic novels that supposedly provide background for the story. (Thus the beginning of the film is labeled part four, an annoying start.)

Attempts to turn “Southland Tales” into a cult film are well under way, but don’t believe it. It’s a mess of apocalyptic proportions.