If we must have more installments in the Marvel series of superhero movies, one can only hope that they’ll all be as much silly fun as “Thor: Ragnarok,” which, under the cheerfully irreverent direction of Kiwi director Taika Waititi (“Hunt for the Wilderpeople”), refuses to take the hammer-wielding son of Odin at all seriously. Waititi not only bypasses the more stentorian tone of Alan Taylor’s “Thor: The Dark World” (2013) by returning to the lighter treatment of Kenneth Branagh’s “Thor” (2011), but goes much further than Branagh did, giving the new movie a comic spin even in the action scenes.

Thor has never been the brightest bulb on the comic-book block, of course, but here he’s depicted as a likable piece of lunkheaded beefcake constantly getting zapped, bonked and imprisoned—he even has to submit to having his golden tresses cut off against his will (and by a trembling old coot fans will recognize). And he always needs the help of others in getting out of the scrapes he’s stumbled into. This Thor might not be especially godly, but he’s an engaging lug, especially as played by Chris Hemsworth, who makes him determinedly obtuse.

In fact, when Thor is first encountered in “Ragnarok,” he’s in a cage, and is soon discussing his fate with a big CGI villain who plans to annihilate Asgard, in the process explaining—fortunately for those viewers unacquainted with the mythology—what “Ragnarok” means (the final destruction of the realm). Thor defeats the gigantic fellow, of course, and returns his crown—the source of his power—to Asgard for safekeeping.

What he finds there, however, is disquieting. His mischievously malevolent brother Loki (Tom Hiddleston), who’s not dead after all, has exiled Odin (Anthony Hopkins) to earth and taken over the realm by posing as him. The two go to earth—Loki reluctantly—to find their father, and after a brief encounter with Dr. Strange (Benedict Cumberbatch)—in which, of course, Thor fares none too well—they find him. But Odin is ready to die, and not only because his daughter Hela (Cate Blanchett), the Goddess of Death whom her brothers knew nothing about, is returning from banishment to claim Asgard for herself as Odin’s first-born. The level of sibling rivalry increases astronomically, and Hela’s powers prove too great to overcome.

That leads to Thor and Loki being thrust into the vastness of space. While Hela systematically takes over their home realm using a minion named Skurge (Karl Urban) as her unwilling enforcer, they separately wind up on the junkyard planet of Sakaar, where an effete ruler called the Grandmaster (played with goofy glee by Jeff Goldblum) conducts an intergalactic gladiatorial combat not unlike Mad Max’s Thunderdome, but on a much bigger scale.

Whom should Thor be pitted against in combat but his erstwhile comrade-in-green-arms The Hulk, aka Bruce Banner (Mark Ruffalo)? After their protracted bout, they will join forces to escape, along with butt-kicking ex-Asgardian Valkyrie (Tessa Thompson), now a bounty hunter who captured Thor in the first place, and sympathetic rock-man Korg (Waititi via motion-capture). Along with the ever-untrustworthy Loki, they return to Asgard to confront Hela, where they find the sentinel Heimdall (Idris Elba) shepherding as many of the populace as possible to safety.

All this sounds typically heroic, and after a fashion it is, of course. But it’s also played with a light touch, and lots of humorous asides. Ruffalo makes Banner’s anxiety a source of fun, Hiddleston oozes cheeky sleaze as Loki, Thompson gives Valkyrie a touch of a dissolute Wonder Woman, and even Blanchett and Hopkins send up their characters as if doing loony Shakespearean riffs. It’s Goldblum, however, who seals the deal with a wonderful hammy turn delivered with perfect deadpan timing, which he continues into one of the inevitable tags during the final credits.

Of course “Ragnarok” doesn’t stint on big CGI-laden chases and battles; this is a Marvel Universe movie, after all. They’re all handled well by the usual army of special effects artists. The more ordinary sets are imaginatively fabricated by able production designers Dan Hennah and Ra Vincent, and the costumes designed by Mayes C. Rubeo are appropriately outlandish (Goldblum seems to delight in his flowing robes, while Blanchett must have been poured into her dominatrix outfit). Editors Joel Negron and Zene Baker are in tune with Waititi’s sprightly vision, while Mark Mothersbaugh contributes a score less bombastic than what often loads down such fare, supplemented at a few important moments by some pop-rock tunes.

“Thor: Ragnarok” is no masterpiece: it’s still a comic-book superhero movie, after all, and a Marvel product at that. But in a genre that often seems more intent on pummeling you into submission than giving you a good time, its light, breezy approach is a breath of fresh air.