I’ve never been a great admirer of Robert Rodriguez. Like Quentin Tarantino, Martin Scorsese and Jean-Luc Godard, the 46-year-old, Texas-born filmmaker is a self-taught “student of cinema,” a one-man crew — oftentimes assuming the role of editor and director of photography, in addition to directing — and like Tarantino, he has an affinity for trashy exploitation cinema. 

However, unlike Tarantino, Rodriguez doesn’t quite have the same ability to take that movie love and transform it into something unique and substantial. He’s made fun movies in the past (“From Dusk Till Dawn”), but even his best movies have more style than substance. 

After he made the 2007 “Grindhouse” homage “Planet Terror,” he began repeating himself. He came out with yet another “Grindhouse” parody, “Machete” — based on a fake trailer made for “Planet Terror” — a mildly entertaining, popcorn movie, but the joke had already been mostly played out. 

After that, he went on to make a fourth “Spy Kids” movie — one that used Smell-o-vision — and then a “Machete” sequel, “Machete Kills.” 

And now he’s made yet another sequel, this time to 2005’s “Sin City,” with “Sin City: A Dame to Kill For.” 

And like “Machete Kills,” “Dame” is repetitive, boring and ultimately pointless.

The original “Sin City” was a solid picture, an old-fashioned film noir with comic-book physics. Characters can jump off high buildings without getting hurt. It’s essentially a male comic-book nerd’s dark, seedy interpretation of film noir.

In “Sin City,” the males are hardboiled vigilantes spouting Phillip Marlow-esque dialogue or despicable sadists, while the women are either hookers or strippers. What made the original slightly more interesting than an average pulp crime picture was the dazzling visual style that walked the line between animation and live action. The black-and-white, rainy, dreary panels — with splashes of color-- from Frank Miller’s original comic books — were brought to life on the big screen. All the environments were added in via postproduction, and the actors were coated in digital makeup. 

The same visual style is back in “A Dame to Kill For,” and it’s really the only thing that makes the movie somewhat watchable. But Rodriguez and co-director Miller don’t bring any new innovation to the visual style. 

The movie consists of thinly written yet still confusing vignettes — all involving revenge in some way or another — that are vaguely connected but don’t flow with each other very well and contain hollow shells of characters. 

All the characters from the first movie are back — minus the ones who died —but they may as well be new ones. The key purpose of sequels is to deepen the characters and further explore the world; “A Dame to Kill For” does neither. 

Mickey Rourke as the hardened character Marv was one of the best parts about the original, and yet, in the sequel, he’s left playing second fiddle to the less-interesting characters Nancy (Jessica Alba) and Dwight (Josh Brolin), as they carry out their various revenge plots. 

Brolin does the best he can with the part, but unfortunately he’s saddled with the film’s stupidest moment. After being double-crossed and beaten up by devious dame Ava (Eva Green), his plan is to infiltrate her mansion disguised as an assassin hired to kill Dwight. His disguise consists of only a new hairdo, and he’s instantly discovered. 

Joseph Gordon-Levitt makes a small impression as Johnny, a fresh-faced, cocky gambler that gets in over his head when he arrives in Sin City. But even he’s reduced to a tiny vignette — split into two parts — that mostly consists of him winning in poker and getting beat up for it, only to end in a disappointing anticlimax. 

However, it’s the female characters that are given nothing to do, except look sexy: They’re all either hookers or prostitutes. While these strippers and hookers do tote guns and do a fair share of butt-kicking, they’re still wearing skimpy outfits. 

Eva Green’s diabolical femme fatale controls men through sex; she spends three-quarters of her role naked. And poor Jessica Alba: She spends the majority of her role stripping at a strip club or guzzling vodka. 

The constant film noir narration by the multiple characters gets annoying. I know narration is a trademark of the genre, but even the great classic noir protagonists didn’t talk over every scene. In “Sin City” no detail is left undescribed. 

I hate to write off Rodriguez as a filmmaker but based on the way he’s going now — making sequels that no one asked for — I’d say he hasn’t an original idea left.