In the DC Expanded Universe of films, which appears to be winding down, there’s only one hero who brings an instinct for fun to every scene, along with an awareness of his own ridiculousness, and that’s Aquaman. Specifically, that’s Aquaman as played by Jason Momoa, who refashioned the half-human Prince (and later King) of Atlantis, aka Arthur Curry, as a brawny, long-haired, beer-chugging, high-fiving, wisecracking bro who bears quite a bit of resemblance to an actor named Jason Momoa.  

Momoa achieves peak Momoa in “Aquaman and the Lost Kingdom,” a neon submarine wreck of a sequel wherein the big guy tries to save the planet from returning bad guy Black Manta, aka David Kane (Yahya Abdul-Mateen II), who wants revenge against Aquaman for killing his dad in the first movie, and has allowed himself to be possessed by the spirit of the Black Trident, which was forged by denizens of the seventh kingdom of Atlantis, a necropolis filled with demonic creatures. Black Manta is dangerous to himself as well as others, and not as in control of the awesome weapon he wields as he thinks he is. His  plan involves the use a glowing green ancient power source that’s like radiation times a zillion, and is accelerating the pace of climate change (the film’s title is etched into the face of a collapsing glacier). 

Not a good situation at all. Definitely the kind you’d want Aquaman to handle.

Momoa is the best reason to see the movie. He’s as alpha-cool, even jerk-ish, as a “maverick” action star can be while also making you believe his character is fundamentally decent and knows when he’s gone too far and sincerely feels bad about it. And he’s got range. One minute, Momoa will practically be doing his own smart-alecky running commentary on the film he’s in, and in the next he’ll weep bitter tears or scream out in anguish or vengeful fury over some dastardly action by a bad guy, as if he’s acting in a silent-movie melodrama with title cards. 

And it all works. The self-awareness never becomes self-conscious or off-putting. Rather than give viewers emotional whiplash, Momoa leads them on to the next scene (or mode) in a way that makes it feel as if it’s all of a piece. (By the way, our hero has an infant son in this one—by his wife Mera, played by Amber Heard—and there are Pixar-style obvious but can’t-miss jokes about the kid keeping the parents up all night. Momoa’s movie star bona fides are confirmed by the belly laughs that he gets from the baby.)

The second-best reason to see the film is Momoa’s chemistry with his co-star Patrick Wilson, returning as Arthur’s half-brother Orm Marius, aka the Ocean Master, the deposed would-be king of Atlantis and Arthur’s chief rival in the first movie. Wilson seems to have been warped into contemporary Hollywood from a much-earlier decade. He has a Van Heflin quality in this one (Matt typed, for the benefit of any oldsters and Wikipedia consulters who might be reading). He is as dry in this role as a man playing an ocean-dwelling humanoid could be. He plays Orm not just as a guy who’s never in on the joke, but doesn’t seem to know what jokes are. That makes him the perfect foil for Momoa’s Arthur Curry, who refers to Orm as “little brother” (despite lil bro’s repeated attempts to destroy him in the last film) and messes with his head as only a big brother can. Arthur is never more infuriating to Orm than when he’s barreling through life, crashing and smashing his way past obstacles, somehow coming out unscathed, and grinning at Orm as if he had a plan the whole time.

Returning director James Wan and screenwriter David Leslie Johnson-McGoldrick (one of Wan’s go-to collaborators; he wrote the first “Aquaman” and two “Conjuring” sequels) don’t waste a lot of time either setting up the story or laboring to convince us that the rest of the cast of the first film (including Temuera Morrison and Nicole Kidman as Arthur’s dad and mom, and Dolph Lundgren as Mera’s father Nereus) had dramatically sound reasons for staying out of the way so Momoa and Wilson could carry the picture. Probably two-thirds of this sequel’s running time is devoted to Arthur and Orm doing the argumentative buddies-on-a-mission thing, with a bit of estranged-brothers-reconciling, plus dashes of redemption narrative, lessons learned, and admitting you were wrong so that you can grow. 

This is a fun movie, but not anywhere near a great one. It lacks the go-for-broke bigness of the original, with its flagrantly melodramatic family dynamics and knowingly ludicrous spectacle (like the seahorses that whinnied and the sharks that roared). There’s a cluttered too-muchness to the production. You may get the sense that there was chaos behind the scenes, and stuff that was staged and shot with the intention of having it play out full-length had to get pulverized and reconstituted in the editing to make the totality work for audiences and exhibitors. The narrated-by-Aquaman opening montage plays like an attempt to shave 20 minutes off the running time and get scene-setting and expository throat-clearing out of the way so the movie could jump ahead to the bits with the brothers getting in and out of trouble and working through their relationship issues while toppling statues, punching giant bugs. and zapping people with laser guns. 

“How many influences do you think they referenced in this?” my viewing companion asked afterward. I wouldn’t dare offer a number, but the film is upfront about its fondness for “Star Wars,” Jules Verne, H.P. Lovecraft, Peter Jackson’s “Lord of the Rings” trilogy, the “Matrix” films (in particular, the sentinel bots) and the works of H.G. Wells (one spectacular extended action scene is built around Arthur and Orm trying to fend off a “War of the Worlds”-like tripod machine). We follow the duo through a dazzling variety of settings, including the aforementioned necropolis, which Wan has said is modeled on Mario Bava’s “Planet of the Vampires,” and a secret underwater lair constructed from the wrecks of pirate ships, and a volcanic island full of green-goo-mutated flora and fauna that’s like something Ray Harryhausen would have stop-motion animated in the ’60s (the Harryhausen showcase “Mysterious Island,” based on H.G. Wells’s novella, is a charming fantasy adventure that’s perfect for young kids, by the way).