Zhang Yimou is one of China’s (indeed, the world’s) most esteemed directors, but with “The Great Wall” he proves that he can make a big-budget fiasco as junky as any Michael Bay behemoth. It isn’t that Zhang can’t handle spectacle; “Hero” certainly demonstrated he can—as did his handling of the Beijing Olympic ceremonies in 2008.

But probably no one could have made much of the ludicrous script cobbled together by Carlo Bernard, Doug Miro and Tony Gilroy, which resembles no other recent would-be blockbuster more than “Warcraft.” The idea is that the Great Wall was constructed as a defense against a horde of man-eating CGI monsters called the Taotie, which—we’re informed through laborious expository material, most of it delivered by “imperial strategist” Wang (Andy Lau)—were unearthed from their underground lair in the mountains by gold-seekers and have since, every sixty years for some reason, launched assaults on the empire, led by their ravenous queen (who acts, apparently, like the queen of a hive of ants or bees, dispensing her orders by sounds she emits). The wall—which, we’re informed in an opening scroll, took 1700 years to build (a figure that might give even Donald Trump pause)—was built to prevent the creatures from reaching the capital, and manned by thousands of troops (all members of what is called “The Nameless Order”) trained in various modes of combat and using an enormous panoply of weapons.

One of those weapons, the extremely secret “black powder”—i.e., gunpowder—is what has drawn outsiders William (Mark Damon) and Tovar (Pedro Pascal) to China: long-time mercenaries and pals, they want to acquire the substance and take it back West. They arrive, bearded and bedraggled, at the Wall just as the Taotie are about to begin their assault. Fortunately, William, a master archer, has killed one of the beasts along the way, and when he and Tovar prove their mettle in the initial battle, they will become trusted allies of General Shao (Zhang Hanyu) and his chief lieutenant, pretty Commander Lin (Jing Tian), who has, happily, learned English from long-time western “guest” Ballard (Willem Dafoe), who long ago came after the powder himself and still wants to escape with it.

Much of the movie is taken up with repeated attacks by the Taotie on the Wall (culminating in a battle with them in the capital itself), and Zhang shows intermittent flashes of his dexterity in arranging big set-pieces involving shifting colors and blocks of leaping, gyrating combatants. But despite his efforts, along with those of cinematographers Stuart Dryburgh and Zhao Xiaoding, editors Mary Jo Markey and Craig Wood, production designer John Myrhe and costumer Mayes C. Rubeo, nothing here has anything like the intoxicating effect of the visuals in “Hero,” “House of Flying Daggers” or “Curse of the Golden Flower.” It certainly doesn’t help that the visual effects are, though garish, decidedly unimpressive; the swarms of Taotie look like amorphous blobs, though the queen does get some impressive close-ups.

Nor does Zhang, who has directed some of the most sensitive and affecting personal dramas to come out of China, manage to bring the slightest touch of authentic humanity to the predictable romance that develops between William and Lin, or to the brotherly back-and-forth between William and Tovar. Both those elements of the picture are shot through with puerility, as can also be said of the subplot featuring boyish Lu Han, as a callow, klutzy warrior who eventually exhibits a degree of courage beyond his years.

Perhaps it was unfamiliarity with English that induced Zhang to assent to stage scenes with such banal dialogue, which even Damon and Dafoe seem to have trouble delivering with a straight face (the Chinese actors appear to have less trouble with it). The presence of the two Americans (as well as Chilean Pascal) is an obvious nod in the direction of audiences in the States, where, it is presumably hoped, the expensive picture might have as much box office success as it has already managed to amass in China. But the ploy is unlikely to attract viewers on this side of the Pacific, who have already started turning their backs on this sort of comic-book level action picture.

But the “western” thread in “The Great Wall” shows that the attempt to “globalize” these sorts of big-budget extravaganzas is hardly a one-way street. For some years Hollywood has been not-so-quietly inserting Chinese subplots and stars into its action pictures to appeal to the international market. Though this is a co-production, it’s apparent that the Chinese have taken up that approach and hope to profit from it. But for it to work, the movie has to be a good one. This “Wall” shows so many cracks that it’s amazing it stays up on screen for two hours, which is about as long as the theatres unlucky enough to have booked it are likely maintain it on their schedules.

As for Zhang, he remains a filmmaker of undeniable talent; one can but hope this will be but a painful aberration for him, and that he won’t get involved in such a massive misfire again. As for Damon, he gave up “Manchester by the Sea” for this?