Even back in 1981, during the heyday of slasher movies with holiday-themed titles that had begun with “Halloween,” the original version of “My Bloody Valentine” was seen as a distinctly second-tier entry in a genre that wasn’t deluxe to begin with. And updating it with all the modern splatter pizzazz one can muster—including 3-D—doesn’t help matters much. It’s still pretty stale stuff, like a box of year-old chocolates.

The threadbare plot still centers on a homicidal wack job loose in a modest-sized mining town who dons the duds of an underground worker—including a gas mask that not only hides his identity but, given the heavy breathing, allows him to sound like a poor cousin of Darth Vader—and wields a pickaxe to skewer innumerable victims. The slaughter, we’re informed in a chronologically clumsy prologue, stretches back more than a decade, when a miner named Harry Warden became the sole survivor of a tunnel collapse by killing the co-workers he was trapped with in order to keep all the air for himself. After being rescued, he lapsed into a coma, but arose on Valentine’s Day, massacred the hospital staff and then took up his weapon of choice to wipe out a bunch of teenagers having a party at one of the mines. Among those who escaped were Tom Hanniger (Jensen Ackles), the son of the mine-owner who was already being blamed for the earlier accident, his girlfriend Sarah (Jaime King), and scuzzy Axel Palmer (Kerr Smith), who carries a torch for Sarah. Homicidal Harry, it appears, is killed by Sheriff Burke (Tom Atkins).

Ten years later Tom returns to town—it’s revealed that he left abruptly after the massacre and hasn’t been heard from since—in order to sell the mines, which he’s inherited from his late father. Axel is now married to Sarah, and now sheriff. Tom’s reappearance sets off a triangular skirmish between him, Axel and Sarah, but more importantly a new slaughter when a masked miner shows up and begins bloodily wiping out people again. Some are logical targets, like mine workers; others seem arbitrarily chosen, like motel guests. But the question is: who’s the culprit? Has Harry—whose body was never found—come back? Is Axel’s rage over his wife’s interest in Tom—and his infidelity with Megan (Megan Boone), who’s just announced she’s preggers—sent him over the edge? Is there something wrong with his oddly restrained deputy (Edi Gathegi)? Does Burke not like retirement? Is irascible, sharp-tongued old miner Ben (Kevin Tighe), who lives in an improbably palatial house, taking vengeance for some perceived wrong? Or is Tom the perpetrator?

To be frank, the “Whodunnit?” aspect of the script doesn’t work. Not only is it extremely old-fashioned in its effort to provide a “logical” and “suspenseful” resolution to a thoroughly nutty scenario, but ultimately it relies on a huge cheat that would have embarrassed even Agatha Christie. But the Swiss-cheese nature of the plot is the least of the picture’s problems. Genre viewers go to these sorts of flicks for shock and awe splatter, and despite the best efforts of director Patrick Lussier, this one really doesn’t deliver. There’s plenty of blood and gore, to be sure, but there are a limited number of ways one can staged pickaxe attacks, and although Lussier tries them all (through the eye, through the throat, directly into the crown of the cranium, into the stomach, etc., etc.), they really lose their punch after the first few attacks. Jazzing up the process by making one victim a naked blonde bimbo who prances about to reveal her talents before getting impaled seems an act of pure titillating desperation, but even it is trumped by making another a little person (happily, the only child in danger is spared). By the close the mayhem has become dispiritingly dull.

And the 3-D effects add surprisingly little. Not that they aren’t sprinkled in well enough—axes, bullets and fireballs fly into the audience along with gushes of blood and occasional body parts, and there’s a moment when a beam of wood impales the windshield of a car in which the camera is situated—but their impact is curiously tame. It’s not the fault of cinematographer Brian Pearson, who had to work overtime with the format, but the visuals don’t save things.

Acting is secondary in this sort of stuff, but it must be said that Kerr and veteran Tighe chew thew scenery ferociously, King makes a simpering damsel torn between two men, and Atkins looks understandably bored. As for Ackles, he pretty much repeats his gruffly intense “Supernatural” shtick. But he’s certainly unconvincing in the prologue, when he’s supposed to be of high-school age.

“My Bloody Valentine 3-D” isn’t as awful as the remake of “Halloween,” or as grisly as that of “The Hills Have Eyes,” or as goofy as those of “Prom Night” or “When A Stranger Calls.” Like the retread of “The Texas Chainsaw Massacre,” it’s just drab and disposable rather than offensive, a throwback that’s more of a throwaway. And so on to the upcoming “Friday the 13th” and “The Last House on the Left.” Courage: eventually today’s unimaginative moviemakers will run out of these old gorefests to remake. Of course then they’ll probably start the cycle all over again.