Aquaman made his DC Expanded Universe debut in “Batman vs. Superman” and was part of the ensemble in “Justice League,” but this is the first movie that’s put him front-and-center. The results are enjoyable enough that you may wish Warner Bros. had done it sooner. While it’s not billed as such, this is an origin story, positioning Arthur as a reluctant hero. As conceived by screenwriters David Leslie Johnson-McGoldrick and Will Beall, adapting Mort Weisinger and Paul Norris’ source, Arthur is a mixed-species character who feels alienated from both of the civilizations he embodies. He's the offspring of union between a lighthouse keeper named Tom Curry (Temuera Morrison) and a stranded Atlantean named Atlanna (Nicole Kidman) whom Tom nursed back to health. Atlanna then returned to the sea and was put to death for the sin of birthing a half-human child.

Arthur has long hair and tattoos, a knack for wisecracks, and a fondness for beer. He rejects allegiance to land or sea. He just wants to be left alone. But he still succumbs to prodding by the idealistic Atlantean Mera (Amber Heard), and becomes a uniter at a time when radical forces, led by Arthur’s treacherous half-brother Orm (Patrick Wilson), want to destroy the land-dwellers as revenge for polluting and militarizing the ocean. Arthur is one of those Joseph Campbell-certified, Fated-for-Great-Things heroes, thus the mythically resonant first name. He even has the equivalent of the moment when the future King Arthur pulls Excalibur from the stone.

The movie is overlong and a bit repetitious (as big-budget superhero films tend to be), and its second half is more distinctive than its first because it lets its freak flag fly. But Wan and company mostly do a brilliant job of shaking the algae from cliches. Rather than get bogged down in plot particulars, they concentrate on characterization and performances, production design, costumes—the look, the feel, the vibe of it all.

Every frame has marvelous details that you might not catch on first viewing. The Atlanteans use their mouths to speak, but there are no visible bubbles, only vocal distortion that suggests "bubbly-ness." When the characters aren’t swimming at dolphin speeds, they square off as if they’re standing on a sidewalk, bobbing ever-so-slightly. The water dwellers have lighting supplied by luminous deep-sea creatures and high technology inspired by aquatic animals and plants. Some of the battle armor features oversized crab and lobster claws. In one scene, Mera wears a dress with a collar made of glowing jellyfish and a multicolored seagrass skirt. In an arena sequence, we hear taiko drumming on the soundtrack, and the camera moves to reveal a lone percussionist: a giant octopus.

