Overview: At the height of the First World War, two young British soldiers, Schofield (Captain Fantastic's George MacKay) and Blake (Game of Thrones' Dean-Charles Chapman) are given a seemingly impossible mission.

In a race against time, they must cross enemy territory and deliver a message that will stop a deadly attack on hundreds of soldiers - Blake's own brother among them.

Verdict: The most vulgar visual effect that I saw in a movie last year wasn’t Marvel-ous or otherwise superheroic; it was in “1917,” and depicted the death of a soldier in combat. The soldier is stabbed, and, as he bleeds out, his face is leached of pinkness and turns papery white just before he expires.

The character’s death would have been as wrenching for viewers if the soldier’s appearance remained unaltered and he merely fell limp. Instead, the director, Sam Mendes, chose to render the moment picturesque—to adorn it with an anecdotal detail of the sort that might have cropped up in a war story, a tale told at years’ remove, and that would have stood for the ineffable horror of the experience.

Instead, rendered as a special effect, the character’s end becomes merely poignant—not terrifying or repulsive—making for a very tasteful death.

That tastefulness is a mark of the utter tastelessness of “1917,” a movie that’s filmed in a gimmicky way—as a simulacrum of a single long take (actually, it’s a bunch of takes that run up to nine minutes and are stitched together with digital effects to make them look continuous).

Yet that visual trickery isn’t the fakest aspect of the movie. Rather, the so-called long take serves as a mask—a gross bit of earnest showmanship that both conceals and reflects the trickery and the cheap machinations of the script, the shallowness of the direction of the actors, and the brazenly superficial and emotion-dictating music score.

The story is a sort of “Saving Private Ryan” in reverse, and that reversal is by far the most interesting thing about “1917,” with its suggestion of an antiwar ethos. Somewhere behind the lines in France, a young British lance corporal, Tom Blake (Dean-Charles Chapman), dozing during downtime, is awakened by a sergeant and told, “Pick a man, bring your kit.”

Blake chooses a fellow lance corporal, Will Schofield (George MacKay), a friend who’d been napping in the grass alongside him. The sergeant sends the duo on a special mission: to cross the former front lines, now abandoned by German forces, and take a letter to a colonel who’s with his troops at a new forward position.

That colonel is about to launch an offensive against the apparently retreating Germans, but aerial reconnaissance shows that the Germans are luring the colonel’s two battalions into a trap, and the letter is an order calling off the offensive. What’s more, the battalions to which Blake is being dispatched include his brother, a lieutenant.

Blake is outgoing and earnest, Schofield is a sarcastic cynic, and the implication is that Blake has been chosen for this mission not because he’s necessarily the best soldier to undertake it but because he’s uniquely motivated to complete it—because he knows that, if he doesn’t reach the colonel in time, his brother will be among sixteen hundred soldiers who will be entrapped and massacred.

The darker suggestion, utterly unexplored, is that morale and commitment were issues in the British Army at this latter stage of the Great War (the action begins on April 6th, 1917, and concludes the next morning), and that a soldier without Blake’s personal motive for saving the two battalions might not be trusted to put himself at risk to fulfill it.

What’s clear is that Schofield is dubious about the mission and resentful of Blake for choosing him as his partner. Of course, because “1917” is a film of patriotic bombast and heroic duty, Schofield’s mind will be changed in the course of the action.

It’s only one in a series of painfully blatant dramatic reversals that wouldn’t be out of place in any of the comic-book movies that are so readily contrasted with “authentic” cinema. (For example, while Schofield has the cynicism knocked out of him, Blake—in another overlap with “Saving Private Ryan”—has to confront the painful consequences of his own warm-heartedly humane idealism.)

The script is filled with melodramatic coincidences that grossly trivialize the life-and-death action by reducing it to sentiment: Schofield fills his canteen with fresh milk that he finds in a pail at a recently deserted farm, and eventually feeds an abandoned baby with it; Blake’s reminiscence of the blanket of cherry blossoms that covers his family’s garden is echoed in Schofield’s discovery of cherry blossoms scattered on a river, which serves as a reminder of his duty and a spark of motivation; an ugly but inconsequential swarm of rats in one part of a battlefield presages a single fateful encounter with a rat in another.

Whereas Steven Spielberg’s “Saving Private Ryan” presents an entire army mobilizing to save the life of one soldier, Mendes’s “1917” depicts two ordinary, obscure, and low-ranking soldiers thrust into a mission to potentially save sixteen hundred, and, by implication, the entire British Army, and change the course of the war.

This is a classic idea, one that comes packed with an elegant irony. (For instance, it’s the idea at work in John Ford’s brief and brilliant Civil War episode in “How the West Was Won,” depicting the fateful encounter of two foot soldiers and two Union generals.) And it’s that very irony which Mendes replaces with a lumbering portentousness.

He endows Blake and Schofield with no comparable sense of their own mission, their own disproportionate moment. The script (written by Mendes and Krysty Wilson-Cairns) is imagination-free, which is to say that it endows the characters with no inner lives whatsoever. Have Blake and Schofield ever killed before in hand-to-hand combat?

How far along are they in their military experience? What have they experienced of the war? For that matter, who are they? What do they think? Where are they from? What did they do before the war? What are their ambitions beyond survival?

What’s especially revealing about Mendes’s superficial and externalized practice in “1917” is that he’s not averse to presenting his characters’ inner visions and states of mind. In “American Beauty,” he famously showed the middle-aged male protagonist’s sexual fantasy of a naked teen-age girl being covered in a sprinkling of rose petals.

While Mendes didn’t shrink from displaying the vivid imagination of a suburban horndog, he’s unwilling to face the imagination of the valorous combatants of “1917.” It’s as if whatever might be on the minds of his protagonists in the course of their dangerous journey toward the front lines, whether fear or lust, frivolity or hatred, would get in the way of the unbroken solemnity and earnestness with which he approaches the subject of the Great War.

(On the other hand, he may fear unleashing his characters’ imagination, because, when, in “American Beauty,” he let his own imagination loose, the result was a cinematic ickiness of historic dimensions.)

Instead, Mendes shuts down Blake and Schofield and envelops them in a silence of the mind in order not to probe or care what they think. What he substitutes for their inner lives are sequences that exist solely because they make for striking images (a big fire at night, a run through a crowd of soldiers going over a trench wall).

These shotlike compositions that arise from the flow of long takes come at the expense of plot and character, as in a scene of hand-to-hand combat that’s framed in the distance without regard to its mortal stakes and intense physicality.

Once more, violence is moved offstage and prettified. The movie’s long takes, far from intensifying the experience of war, trivialize it; the effect isn’t one of artistic imagination expanded by technique but of convention showily tweaked. Its visual prose resembles a mass-market novel with the punctuation removed.

The film is dedicated, in the end credits, to Lance Corporal Alfred H. Mendes—the director’s grandfather—“who told us the stories.” In honoring the recollections and experiences of his grandfather, Mendes remains trapped in the narrow emotional range of filial piety that, far from sparking his imagination, inhibits it.

His sense of duty yields an effortful and sanctimonious movie that, at the same time, takes its place in a lamentable recent trend. Mendes joins such directors of proud and bombastic craft as Spielberg, Christopher Nolan, Peter Jackson, and Damien Chazelle, who’ve recently made films that are fixated on the heroic deeds of earlier British and American generations.

These filmmakers, celebrating their truncated yet monumental versions of history’s heroes, are separating the public figures from their private lives, their visible greatness from mores that might not pass current-day muster.