In “Damsel,” a deadpan minimalist Western comedy written and directed by David and Nathan Zellner (it’s the sort of movie that provokes more mental chuckles than actual laughs), one of the ongoing dog-whistle jokes is that the movie packs in every last trope and cliché you’d expect to see in a vintage Western. Towering mesas out of Monument Valley. A handsome stranger wandering into a saloon, where he’s surrounded by varmints with bad teeth. A horseback odyssey across the mountains in pursuit of an outlaw. A declaration of romantic devotion pure enough for John Ford. A Native American arrow zipping out of the air. Shootouts and hangings. A shack blown up with dynamite.

None of this is parody, exactly; it’s all served up straight and neat, with the most lavish and stately of cinematography. What nudges “Damsel” gently off kilter is the way that the desperate, scrambling characters lack so much as one iota of classical destiny or larger-than-life force. They look like archetypes (the noble searcher, the wimpy parson, the rootin’-tootin’ tough gal), but they turn out to be the most banal of human beings, who speak in faintly jarring contemporary phrases (they say things like “hassle” and “relationship” and “win-win”) and, in spirit, might be romantic desperadoes out of Williamsburg. They’re a little like the characters in “Blood Simple”: super-ordinary suckers who are free to carve out their own hapless (or ridiculous) fate.

The Zellners know just how to use their star cast. Robert Pattinson, with a gold tooth where his right incisor should be, hits the perfect note of drawling flaked-out good cheer as Samuel Alabaster, the stranger in town, who has hired Parson Henry (played by David Zellner) to come back with him to marry Samuel and his beloved financée, Penelope (Mia Wasikowska). The two men head out of town, with a miniature horse named Butterscotch in tow, and everything seems casual until Samuel informs the parson that Penelope has, in fact, been kidnapped. He needs help in rescuing her.

To reveal more wouldn’t be fair to the film’s surprises, but suffice to say that Penelope, the movie’s damsel, is not in the sort of distress we expect. Pattinson’s performance is clever enough that we have no problem accepting him as the shambling-dude version of a classic good guy, and then, when the film’s plot turns around on him, that same cracker-barrel face suddenly looks like the image of a man who may have a screw loose. We get the first inkling, actually, when he croons a country ode to his beloved called “My Honeybun,” and repeats the word “honeybun” a few too many times. (Not to mention the moment when he demonstrates his devotion by masturbating to her image in a locket.)

The movie unfolds with an invisible wink, yet the pace is so stately and deliberate that at moments one is tempted to call it glacial. The rhythm is no accident; the Zellners know just what they’re doing. (They must be major devotees of Jim Jarmusch’s “Dead Man.”) Yet “Damsel,” if I’m going to be honest about it, is droll and touching and amusing and a little boring, all at the same time. It’s the fourth feature the Zellners have written and directed, and they’ve got a vision here — a knuckleball spin on the Old West, which turns out to be a melancholy existential jape rooted in loneliness. They’re skillful filmmakers. But they need to get our pulses going a bit more, because this movie’s commercial prospects are going to be limited.

Penelope turns out to be the toughest character in the movie: a righteous and self-protective post-feminist Calamity Jane, who takes out her bent shotgun and uses it only because of how badly she’s been wronged. She has no patience for any man who would destroy her happiness. Wasikowska, under a chopped wedge of blonde hair, gives her true grit; her straight-shooter line readings are punchlines of rationality. She’s as alone in the world as any of the other characters, but she’s the one who won’t be dragged down.

“Damsel” often feels like a ride in slow motion. Yet unlike “Blood Simple,” which kept twisting itself into new shapes, the twists in this movie don’t come thick and fast enough. The most encouraging thing about the Zellner brothers is that they don’t overplay their jokes — they savor them. Like, for instance, the deep-voiced Indian, played by the sensational Joseph Billingiere, who shows up near the end and basically finds highly dignified Native American ways of saying “Are you f—ing kidding me?” “Damsel” is a comedy of attitude made with the indulgent touch of an art Western. That’s a refreshingly original thing, though it’s not as blow-you-away cool as the filmmakers seem to think it is.