You needn’t be a devotee of Jane Austen to be aghast at “Pride and Prejudice and Zombies.” Not, however, because the idea of inserting a battle with the undead into her most famous novel is beyond the pale—in fact, the premise has possibilities—but simply because it has been so badly flubbed.

The movie, adapted from Seth Grahame-Smith’s novel by Burr Steers (who also directed), is a strange beast, of course—as was “Abraham Lincoln: Vampire Hunter,” also based on a book by Grahame-Smith. But the earlier movie had the courage of its goofiness: director Timur Bekmambetov told the ludicrous tale with over-the-top visual style. By contrast Steers’ treatment is flat-footed: as difficult as it is to imagine that a mash-up this absurd could be dull, the movie manages to be a snooze.

The best element in “PPZ,” as the picture has been dubbed, is the “PP” part, but only by default. No one will confuse Steers’ treatment of Austen’s nineteenth-century comedy of manners with Robert Leonard’s or Joe Wright’s, but at least it has a degree of period elegance thanks to Dave Warren’s production design, Julian Day’s costumes and Naomi Moore’s sets—even if cinematographer Remi Adefarasin gives his widescreen images a slightly blurry look and the sound team has bungled its job, allowing much of the dialogue to be muffled. (Fernando Velazquez’s score is no help: it’s slathered on too thick, and especially in the first reel feels compelled to italicize the jokes in the style of a heavy-handed farce.) To be sure, you have to accept an Elizabeth Barret (Lily James) who’s a thoroughly modern miss, pretty much a proto-feminist though one trained, in view of the constant threat of zombification, in Shaolin warrior technique. Still, the movie does preserve the marriage-obsessed concerns of the Bennet clan, even if it adopts a sitcom-based approach to the characters of Mrs. Bennet (Sally Phillips) and Pastor Collins (Matt Smith).

It’s when one gets to the “Z” part of the picture that things really fall apart. Simply put, Steers seems to have no feel for staging action scenes or choreographing combat. The bits that come off best in that regard are ones that have a basis in Austen, and add physical elements to her verbal skirmishing. When Elizabeth angrily rejects the first proposal of Darcy (Sam Riley), for instance, their argument is a mixture of language and martial-arts face-off, and though even here the staging is clumsy, it brings together Austen and Grahame-Smith as well as one could hope. A similar effort toward the close—in the confrontation between Elizabeth and Catherine—isn’t nearly as cleverly done, but at least it attempts a similar mesh.

For the most part, however, the zombie element in the picture is poorly handled. Even “The Walking Dead” offers more arresting tableaux of hordes of the undead moving across the landscape than “PPZ” does. And when the brain-eaters are confronted by the unaffected, Steers and his editor Padraic McKinley simply go bonkers, cutting the footage into blips so short and chaotically assembled that it’s virtually impossible to discern what’s going on. Even the final confrontation between Darcy and his nemesis Wickham (Jack Huston)—a character to whom Grahame-Smith adds a back-story that strains credulity but allows for a big finale—is sloppily staged (as is the following dash across an exploding bridge). Of course, the messiness of that bridge scene is also due to special effects that are at best mediocre.

The actors don’t fare well under Steers’ hand. Riley and James make an attractive pair, but James in particular is encouraged to push too hard, while Riley wisely holds back in the knowledge that in this sort of lunacy restraint pays dividends (a lesson that Huston might have learned). Bella Heathcote and Douglas Booth have the easier task, since as Jane Bennet and Mr. Bingley they merely have to look like the decorous couple they’re destined to be, and both are very easy on the eye. The inevitable Charles Dance is wasted as Mr. Bennet, who fades so far into the background here he might as well be absent.

“Pride and Prejudice and Zombies” is ultimately an opportunity lost, a movie that might have been a gonzo classic but instead proves a disappointing damp squib. (One can only imagine what it might have been like starring Natalie Portman, who was once rumored for Elizabeth and is still one of the producers, and/or directed by David O. Russell, who was reported to be attached to the project.)

But at least we can all look forward to “War and Peace and Werewolves.”