Pity Paul W.S. Anderson. He’s directed so many awful movies, most of them with “Resident Evil” and “Death Race” in the title, that Sony-Tristar ineptly elected to dump his “Pompeii” at the end of February, to hide it from movie critics until after the last minute.

What Anderson delivers this one time is a genuine spectacle, a gladiator movie with a volcano in the middle of it. “Pompeii” has a first-rate effects team that recreates the living hell of Pompeii as it is buried under ash, pumice and fire. It has a fight choreographer from “300.”

And though I thought I’d never type these words in association with a Paul W.S. Anderson picture, it’s not half bad. The acting is flat, the story is corny and old-fashioned and takes too long to get going. The dialogue is a tad old school, too. (“Is this the end of the world?”)

But the fights are furious. And one hour in, when Mount Vesuvius does what we know it did in 72 A.D., this is about as close to the real deal as we’d ever want to see.

Years before that eruption, a boy survives the massacre of his British Isles family at the hands of the Romans. He’s sold into slavery and grows up to become “The Celt”— able to cut up guys literally twice his size.

That’s when Milo, the Celt (Kit Harington of “Game of Thrones”), is shipped off to Pompeii, to fight in the arena and become smitten with a young noblewoman, Cassia (Emily Browning). Her parents (Carrie-Anne Moss and Jared Harris) would never approve. But since she’s being pursued by the evil Senator Corvus (Kiefer Sutherland), maybe Milo has a shot.

“I will break you,” the senator sweet-talks her, “and you will STAY broken.”

Too bad that Cassia’s dad is a developer in need of the backing of a prominent Roman for his grand planned remaking of the city. Yes, he’s beholden to the senator. And yes, 2,000 years ago developers were still trying to make a fast buck on land no sane person would build on.

Because with every rumble, every “Vulcan is speaking to us” belch from the volcano, Vesuvius lets us know that the third act is coming and it’s going to be a doozy.

Anderson, a graceless and heartless filmmaker on most projects, lets only a hint of humanity make its way into “Pompeii.” The opening shots are of body molds, preserved by ash, pitiful images of suffering that humanized this historical tragedy. The film also makes us feel something, here and there — a child separated from her mother, lovers having a last doomed embrace.

Jean Frenette’s fights, hurling Harington against the charming hulk Adewale Akinnuoye-Agbaje, are first rate. And Sutherland makes a perfectly venal villain.

“Pompeii” isn’t anybody’s idea of high art or flawless history. It’s too long, there are few light touches and the leads don’t have enough moments to set off sparks that aren’t volcanic in origin. But it has more heart than your average sword-and-sorcery piece, and effects that could have lifted Anderson out of the Z-grade “Resident Evil” sequels he’s been churning out since Hollywood gave him his green card.

He could have escaped his past, if only his studio had let him.