Rising from an early grave of negative pre-release publicity, director Marc Forster and producer-star Brad Pitt’s much-maligned “World War Z” emerges as a surprisingly smart, gripping and imaginative addition to the zombie-movie canon, owing as much to scientific disaster movies like “The China Syndrome” and “Contagion” as it does to undead ur-texts like the collected works of George Romero. Showing few visible signs of the massive rewrites, reshoots and other post-production patchwork that delayed its release from December 2012, this sleekly crafted, often nail-biting tale of global zombiepocalypse clicks on both visceral and emotional levels, resulting in an unusually serious-minded summer entertainment whose ideal audience might be described as comicbook fanboys who also listen to “Democracy Now.” Opening a week apart from the more four-quadrant-friendly “Man of Steel” in most markets, “World War Z” should post solid enough numbers at home and abroad, but with a rumored final cost well north of $200 million, it’ll need more than a bit of kryptonite up its sleeve to push far into profitability.

A flexible metaphor for all manner of social, cultural and political maladies, the zombie genre has, over the decades, been employed as an analogue for everything from the U.S. occupation of Haiti (1932’s Bela Lugosi starrer “White Zombie”) to the upheaval of the Vietnam/civil rights era (“Night of the Living Dead”) and the bio-panics of the late 20th century (“28 Days Later,” “Resident Evil”). Significantly expanding the claustrophobic geography of most zombie pics, the aptly titled “World War Z” doesn’t have a particular polemical axe to grind so much as it seeks to imagine how the world’s ideologically disparate peoples and governments would respond if great masses of the populi did suddenly turn into rabid, flesh-eating beasties. In what may be taken as an affront by the America First crowd, the old U.S. of A. descends into chaos pretty early on, while the two nations best equipped for the coming onslaught turn out to be Israel and North Korea — the former by building an enormous wall, the latter by extracting the teeth of its entire population. No biting, no zombies, see?

Not that any makeshift solution lasts for long in “World War Z,” whose undead prove terrifyingly hardy and lightning-quick, sprinting into spastic action when they sense fresh meat is near and turning their victims into fellow travelers in a matter of seconds. We first seem them wreaking havoc on a downtown Philly traffic jam — a genuinely spectacular and unsettling orgy of mob panic from which world-weary ex-United Nations investigator Gerry Lane (Pitt) barely emerges with his wife, Karen (Mireille Enos), two young daughters and own body fully intact. Fleeing in a stolen camper, they hightail it to Newark, where they await extraction from Gerry’s former U.N. boss, Thierry (the excellent South African actor Fana Mokoena), but not before waiting out the night in a rundown apartment building transformed by Forster into a skin-crawling succession of winding, shadowy corridors and flickering fluorescent bulbs. (The generally arresting cinematography is credited solely to Michael Bay collaborator Ben Seresin, though the pic was begun by Oscar winner Robert Richardson.)

Adapted by a small army of screenwriters from the bestselling novel by Max (son of Mel) Brooks, the pic abandons its source material’s choral “oral history” structure to hone in on the Lanes, who, after once again negotiating a narrow escape, find themselves ensconced in the relative safety of an aircraft carrier somewhere in the Atlantic. At this de facto command center for what remains of the U.S. military, Thierry wastes no time in giving Gerry an ultimatum: Go back into the war zone on the U.N.’s behalf, or else be sent right back to zombie-infested Philly with his family in tow. And from there, “World War Z” hopscotches the globe, as Gerry (in the company of various military escorts) searches for the proverbial “patient zero” and the possibility of a cure.

PHOTOS: Brad Pitt, Angelina Jolie Attend ‘World War Z’ Premiere

Something the writers and Forster have cribbed well from the Romero playbook: They waste little time with scene-setting niceties, plunging us straight into the thick of zombie mayhem, and, Pitt notwithstanding, they don’t afford anyone star treatment. Characters who initially seem poised to become significant supporting players — among them Army Rangers James Badge Dale and Matthew Fox and rogue CIA operative David Morse — prove expendable, either by becoming food for the encroaching zombie horde, or simply by virtue of the pic moving on to another locale: first a ghostly military base in South Korea that might be the source of the outbreak; then to Israel, where a senior Mossad agent (well played by Dutch filmmaker Ludi Boeken) may hold some additional clues; and finally a WHO research lab in Wales, where — in the pic’s most elegantly crafted setpiece — Gerry and a handful of uninfected scientists enter into a careful cat-and-mouse game with the otherwise zombified staff.

Considering the incoherent shambles he made out of his James Bond movie, “Quantum of Solace,” Forster handles the large-scale action here with considerable aplomb and much striking imagery, enhanced by the seamless mix of choreography, prosthetics and CG that bring the herking, jerking zombies to “life.” That these zombies have particularly sensitive hearing allows Forster and his sound designers a field day with creaking doors, broken glass crunching underfoot, and in one especially tense moment, a soda can rolling across a cafeteria floor. Moreover, the director always keeps the movie rooted in a compelling dramatic situation, with Pitt giving a very appealing turn as the seen-it-all veteran of the world’s worst places whose desire to protect his family trumps his desire to save the world. By today’s standards, he’s a refreshingly human-scaled movie hero, with no outsized strength, agility or superpowers to help him win the day.

Despite having little screen time and even less dialogue, the marvelous Enos manages to suggest a full range of wifely and motherly emotions through the subtlest of glances and smiles that mask her pain. Israeli-born newcomer Daniella Kertesz also makes a strong impression as the soldier who accompanies Gerry on the last leg of his journey, including a harrowing Jerusalem-Cardiff flight with some most unfriendly passengers in coach.