The good news is that Tim Burton’s take on Dan Curtis’ infamously campy sixties gothic soap opera isn’t the ghastly disaster the trailers seemed to indicate. For the first hour or so, “Dark Shadows” is actually an affectionate tweaking of the show, incorporating both the director’s flair for stylish ghoulishness and his love of quirky humor, this time employing the character-out-of-time ploy in a way that only occasionally stumbles into groan territory (as in the television gag featured much too prominently in the previews). And it’s a fine showcase for another of Johnny Depp’s wonderfully eccentric performances as Barnabas Collins, the two-hundred-year-old vampire resurrected from his grave who moves in with his oddball family of descendants.

Unfortunately, as happens so often nowadays, in its last half the movie degenerates as it strains to go the spectacular route, getting all twisted up in plot contortions and culminating in a florid special-effects extravaganza that tosses in everything but the kitchen sink (though it does include bronze statues that come to life and a falling chandelier, redolent of “Phantom of the Opera”). In the end the delicate oddity that enlivens the earlier portion of the picture evaporates in an orgy of big-budget mayhem.

Still, there’s a touch of genius to Depp’s wittily deadpan performance, especially in the earlier going. With his flamboyant diction and fastidious carriage, he fashions a figure that may not be the equal of Ed Wood and Edward Scissorhands, but nonetheless represents another of the memorable characters he’s contributed to Burton pictures. There are also fine turns by Michelle Pfeiffer as Elizabeth, the current head of the Collins clan (the character originally played by Joan Bennett), who seems more at ease here than she has on film in years, and Helena Bonham Carter as Dr. Julia Hoffman, the boozy doctor who tries to cure Barnabas of his malady. She opts for a cartoonish approach, but Grayson Hall was no slouch in that department either.

The rest of the cast is less impressive. Chloe Grace Moritz is a one-note bore as Elizabeth’s daughter Carolyn, and a last-act revelation about her is one of the finale’s biggest missteps, while Jonny Lee Miller does little with the part of Roger Collins. Similarly lackluster turns are handed in by Bella Heathcote as Victoria, the modern spitting image of Barnabas’ long-lost love, and Jackie Earle Haley as Willie Loomis, the family handyman. Young Gully McGrath is pretty much wasted as Roger’s little son David, though he does get one good line toward the close.

But the biggest problem with “Dark Shadows” lies in the script’s emphasis on Angelique (Eva Green), the witch who initially cursed Barnabas out of unrequited love and now rules Collinsport, having ruined the founding family. The duel between her and Barnabas becomes the focus of the movie’s second half, and proves a tedious invitation to ever-more elaborate special-effects set-pieces, most of which expend much for very little return (as in a sequence of lovemaking that borrows a trick from Fred Astaire, though his use of it was far better). It doesn’t help that the lovely Ms. Green has all the fizz of a high school girl trying to act sexy and seductive, but even the classiest vamp in the world couldn’t have salvaged such weak material.

As one would expect, visually the movie is a marvel, with Rick Heinrich’s production design, the art direction supervised by Chris Lowe, John Bush’s set decoration and Colleen Atwood’s costumes all contributing to a typical Burtonesque wave of eye candy and Bruno Delbonnet’s cinematography (happily eschewing 3D) capturing it all in a gorgeous haze. And while Danny Elfman’s original score lacks the distinction of his best work, the insertion of some period pieces will satisfy nostalgia buffs (though “A Summer Place” would qualify as a golden oldie in 1972). Alice Cooper shows up to topline the Collins party entertainment, prompting a funny reaction from Depp but otherwise earning few laughs (though it does allow for don’t-blink-or-you’ll-miss-them cameos by some of the old soap’s cast, including the original Barnabas, Jonathan Frid.)

It’s easy to understand why Burton so loved “Dark Shadows” and wanted to pay homage to it—it speaks to the obsession with the outcast and misfit that’s been the central theme of his work, which at its best (“Ed Wood,” “The Nightmare Before Christmas,” parts of “Edward Scissorhands”) conveys the ache of separateness in a uniquely personal style. And it’s no accident that in most of those films Depp is his collaborator. Too bad that “Shadows,” though it has some fine moments, joins “Charlie and the Chocolate Factory,” “Sleepy Hollow,” “Alice in Wonderland” and “Sweeney Todd” as a lesser entry in their growing canon of work together.

To close, a bit of “Dark Shadows” trivia. In 1991 NBC broadcast a misguided prime-time remake of the show. Who played little David? None other than Joseph Gordon-Levitt, who probably leaves the gig off his resume.