The world may be going to hell, but the writer and director James Gunn has graced it with a sunshine “Superman.” The most recent installments in the franchise—Zack Snyder’s diptych “Man of Steel” (2013) and “Batman v Superman: Dawn of Justice” (2016)—had a hectic, howling, near-apocalyptic sense of tragedy, but Gunn’s vision is bright, chipper, and sentimental. Admittedly, there’s a blast of grimness right at the start, but it’s only a ruse. A title card announces that Superman has endured his first defeat, and the hero (played by David Corenswet) is shown tumbling from the sky and slamming with a sickening thud onto the surface of a frozen wasteland, where he lies prostrate, spitting red blood on the snow. Fear not: no sooner does the wounded combatant put his lips together and whistle for Krypto than his faithful and frisky canine companion arrives and drags his master back to the Fortress of Solitude. There, loyal robots examine the patient and, by exposing him to sunlight, begin to heal him. But this is a Superman in a hurry; before he has been restored to full strength, he rushes back to his adopted city of Metropolis, to battle against the challenger who has just laid him low, a hulking mechanized creature known as the Hammer of Boravia.

Boravia is an Eastern European country threatening to invade its neighbor Jarhanpur, a poorly armed—and, pointedly, predominantly nonwhite—state, which Superman is trying to defend. The Hammer proves to be only a puppet for Superman’s old archenemy, Lex Luthor (Nicholas Hoult), who controls him, barking out commands like a TV director. These days, Lex is a tech tycoon and an arms dealer; he is selling weapons to Boravia, a U.S. ally, and has connections at the Pentagon. Taking advantage of Superman’s pro-Jarhanpur activism, Lex stage-manages a huge internet smear campaign, involving such epithets as #Superspy and #Supershit. Superman, trying to take back control of the narrative, makes use of his civilian persona, the journalist Clark Kent, of the Daily Planet, to explain himself—supposedly, Superman has granted Kent an exclusive interview—but his popularity in Metropolis continues to plummet after Luthor releases a video in which Superman’s parents are heard dispatching their offspring to Earth not to benefit the planet but to conquer it. Even Lois Lane (Rachel Brosnahan), Clark’s colleague and romantic partner, who knows about his dual identity, is souring on Superman, leading to a breakup that appears to have been concocted solely to allow the couple a happy-ending reunion. Their relationship has about as much chemistry as if they’d been filmed separately in front of green screens, but losing Lois makes Superman even lonelier and more vulnerable. His isolation gives Lex a perfect opportunity for a fierce Boravian assault on Jarhanpur.

It’s a promising setup, but it’s spoiled by the fact that Superman is unchanged by his travails. He has suffered his first defeat and lost his reputation but gives no thought to these new experiences and never pauses to reflect on his failings. Gunn, rather than zooming in to consider the fate of a natural warrior menaced by a crisis of confidence, pulls back, expanding the cast of characters to include a trio of allies who rally to oppose Lex’s evil schemes: Green Lantern (Nathan Fillion), Mister Terrific (Edi Gathegi), and Hawkgirl (Isabela Merced), who dub themselves the Justice Gang. With these added characters aboard, the action proliferates into tests of coördination and strategy that further distract from Superman’s character and conflicts. When the video of his birth parents makes him wonder whether his destiny is evil, it takes only a trip to his adoptive parents, Martha (Neva Howell) and John (Pruitt Taylor Vince), in Kansas, to set his mind at ease with a moral lesson of trivializing simplicity. Like a job applicant whose avowed worst trait is working too hard, Superman is revealed by Martha to have one real flaw: like John, he’s a “big mush” who’s quick to cry and can’t bear to see people, or animals, suffer.

In other words, Gunn—who not only wrote and directed the movie but is also a co-chairperson of DC Studios at Warner Bros.—has applied to his first movie in the DC universe the formula that served him so well with the three Marvel “Guardians of the Galaxy” movies he made for Disney. Like those films, which established Gunn as an industry leader in the field of spectacular big-budget fantasy, “Superman” is a group movie in which the interactions of many characters, with their gibes and quips and whimsical bonhomie, decorate the churning action, offering catchy distractions but little substance. Most of the work is done not by Gunn’s writing but by the lively cast, whose attitudes and line readings have more personality than the text suggests. Gathegi endows a handful of terse phrases with an especially large dose of attitude.

The result is a team-effort version of Superman. No superhero is an island, and none can save the day alone. Superman is needed in multiple places at once, and he’s never quite super enough to finish even one fight single-handedly. It’s a theme, at least, albeit one that’s not explored any more than the personality crisis that Superman is ostensibly experiencing. Moreover, Gunn’s Superman is less powerful than the protagonist—incarnated by Christopher Reeve—of Richard Donner’s 1978 “Superman,” who additionally wields X-ray vision and a sense of humor. (Corenswet, purging the title character of any trace of camp or ambiguity, is as thoughtful, serious, and matter-of-fact as a superaccountant.)

This cornball “Superman” turns into a grab bag of formats and plot points—some inspired, many not. There’s a kaiju episode of blithering absurdity, in which the corpse of a skyscraper-size dinosaur-like monster seemingly just vanishes rather than, as logic would dictate, leaving Metropolis with a sanitation problem for the history books. There’s an extended science-fiction sidebar about a so-called pocket universe—miniature intergalactic expanses created by a simulated big bang and requiring a chess-like set of rules to manage. This clever yet belabored notion leads to a catastrophe of a sort that’s handled better in the cheesy 1965 science-fiction thriller “Crack in the World” and, for that matter, in the 1978 “Superman.” There’s also a climactic twist so good that it deserves not to be spoiled—a crisis of identity that leads to a rock-’em-sock-’em showdown but smashes to smithereens any hint of psychological significance or personal conflict issuing from that twist’s enticingly vertiginous strangeness. Gunn crafts playful dialogue between Superman and his robotic assistants in the Fortress of Solitude (particularly one voiced by Alan Tudyk), and the peripheral touches extend to a “John Wick” parody, when Superman, bereft of Krypto, rages at Lex, “You took the dog!” In a timely touch, the besmirched and despised Superman comes under official suspicion, and his incarceration is outsourced to a private prison that holds political prisoners as well as the owner’s personal enemies.

In moments when Gunn leaves behind his own virtuous intentions and allows his imagination to run free, the movie catches a spark of life, as when Lex lets fly a soliloquy of envy that, in its snarling grandiloquence, attempts to rival Iago’s self-justifying spew of venom, and when Mister Terrific, searching for Superman, finds him by means of DNA traces that turn into human-size aura-like images. But Gunn has a strange gift for undermining himself. He fills the film with hints of current events, as in Lex’s hate-filled references to Superman as an “alien” and as “it” and in a mention of Superman, as an extraterrestrial, having no legal rights. And yet, Superman’s plan to rescue Jarhanpur, in defiance of the U.S. government—complete with echoes of ongoing real-world conflicts—is presented not as a political commitment but as a manifest mission of good versus evil. The theme of liberal interventionism which had been painstakingly established is shrugged off as no problem. What had seemed like a central issue is revealed as a mere MacGuffin.

Gunn’s skill set in developing a batch of antic characters and episodes proves similarly wide and thin; it’s altogether different from the art of exploring the full potential of an idea or delving into the character of a lonely hero. The superheroic team and Lex’s cabal fight one another amid catastrophes in which fungible people are served up as collateral damage without ever getting individual voices. The top-down superspectacle follows the track of its plot with mechanical obstinacy, reserving its hearty empathy for humanity in general without imagining any particular people in it outside the protagonist’s immediate circle of friends and enemies. All of Metropolis and the world at large—in which Superman claims free scope of action—are simply backdrops. Despite touches of menace, “Superman” feels crafted for children. The sense of evil has nothing cosmic or metaphysical about it; there’s no grandeur and no wonder to Gunn’s universe and, although there’s much discussion of the defining quality of one’s actions and choices, the film’s superheroes seem thin, constrained, and undefined. Gunn is admirably overflowing with imagination, but he squanders his best material. ♦