‘Aquaman’ is no washout, but could have used a little more camp

“AQUAMAN” — 3 stars — Jason Momoa, Temuera Morrison, Nicole Kidman, Patrick Wilson, Dolph Lundgren, Amber Heard; PG-13 (sequences of sci-fi violence and action, and for some language); in general release; running time: 143 minutes

“Aquaman” is weird and corny and fun, but it would have been more fun if the weirdness and corniness had been dialed up to 11.

Director James Wan’s film is the story of how Jason Momoa’s supporting hero from last year’s “Justice League” evolves from shirtless, sarcastic antihero to costumed king of the marine kingdom. The journey has its high points, but the pieces often feel clumsy, and to be honest, the antihero Aquaman is a little more fun.

Wan starts with some back story, showing Aquaman’s parents meeting when his father, Tom (Temuera Morrison), finds Atlanna (Nicole Kidman) washed up on the coast of Maine one dark and stormy night. Atlanna is royalty from the lost civilization of Atlantis, but she falls in love with Tom and has a son, Arthur, who shows unique powers even beyond a normal Atlantian.

This combination of advanced powers and mixed heritage turn Arthur (Momoa) into the exiled proto-Aquaman we saw in the “Justice League” movie, and in this installment, he gets summoned to his rightful underwater home to deal with a rising threat.

In the sunken kingdom of Atlantis, Arthur’s half-brother, King Orm (Patrick Wilson), is trying to unite a group of undersea factions to wage war on humanity, which has polluted the seas for too long. He has a supporter in King Nereus (Dolph Lundgren), but Nereus’ daughter, Mera (Amber Heard), thinks peace is the better move and hopes Arthur’s dual identity can stave off disaster.

First, Mera has to persuade Arthur to get on board with the idea of being king. Then Arthur has to find a lost sacred trident and confront King Orm. In the meantime, Arthur’s also dealing with an Atlantian technology-wielding pirate named Black Manta (Yahya Abdul-Mateen II), who blames him for the death of his father.

It’s a little sporadic, and some awkward exposition tries to fill in a lot of external mythology to keep the story moving. There are plenty of good parts and enough highlights to keep fans happy, but the finished product feels like it could have turned out better in different hands.

Part of the issue is the inherent campiness of the source material — campiness that tends to float to the surface unintentionally whenever the story starts taking itself too seriously. You can only buy so far into a world where people ride the backs of killer whales and are called to fight giant underwater crabs in a place called the Kingdom of the Brine.

Momoa’s wisecracking demeanor helps a lot, and “Aquaman” could have used more of it — perhaps a “Thor: Ragnarok” treatment might have been more appropriate here. And funny enough, “Aquaman’s” tale of exiled redemption and brotherly tension bears some parallels to the first “Thor” movie.

And like “Thor,” “Aquaman” spends most of its screen time in fully CGI environments, which generates positive and negative results. Some of the work looks fantastic, such as the pull-out-all-the-stops finale that caps the third act. Other elements don’t look so great, like the awkward way the Atlantian humanoids move around under water.

There’s enough cheeky bravado to make fans happy, and Wan’s effort is good enough to entertain most people for at least one viewing. But “Aquaman” still lingers under the surface compared to the big screen’s better superhero offerings.

Rating explained: “Aquaman” draws a PG-13 rating for various elements of CGI-driven action violence (including stabbings), some occasional profanity and some sexually-suggestive costumes.