Half the time I was laughing during the bracingly unsentimental coming-of-age comedy "Submarine," I wasn't even sure why. Writer-director Richard Ayoade's adaptation of the Joe Dunthorne debut novel isn't merely joke-funny. It's texture-funny, which is harder, considering the locale: starkly beautiful, gray-toned Swansea, Wales, onetime home of Catherine Zeta-Jones, Dylan Thomas and, according to Dunthorne, an endless supply of sexual frustration.

The unreliable 15-year-old narrator of "Submarine," Oliver Tate, has a way of muttering the never-ending ends of his sentences so that he seems to be chronically unsure of himself, yet he keeps pushing on, in a hilariously arrogant way. Craig Roberts plays Oliver. In the film's production notes, Ayoade speaks of the young actor's audition. "He had a Pete Townshend-ish haircut with a very short fringe, but with big bags under his eyes. He had a pleasing look." Imagine a slightly livelier U.K. edition of the Monkees' Michael Nesmith, with an exquisitely calibrated deadpan arsenal.

Here are the facts of Oliver's life. His parents redefine the concept of "rut." Mother Jill (Sally Hawkins, who speaks exactly the way Roberts does, never quite putting a button on a sentence) may be dallying with her old flame, the New Age "life coach" played by a riotous Paddy Considine. (His character performs bizarre martial-arts maneuvers at the most peculiar times.) Oliver's dad is played by Noah Taylor, who starred in the lovely Australian coming-of-age pictures "The Year My Voice Broke" and "Flirting." These three, together, are magic, yet so understated I suppose some filmgoers might experience "Submarine" as an extended exercise in Not Enough.

Whatever. As he frets about his parents' marriage Oliver obsesses over a fetching young fellow student, a pyromaniac in a Louise Brooks pageboy. Yasmin Paige makes this girl blase in all the right, intimidating ways. The film never goes soft on Oliver, who is a yutz — perpetually spying, weaseling, self-aggrandizing — yet never dull. In an ideal universe, the protagonist of "Submarine" would someday meet the protagonist of Wes Anderson's "Rushmore" and together rule the world.

Remarkably, this is Ayoade's first feature. He finds the honest, romantic ache beneath Oliver's deflections and evasions, and when the boy's confusion demands solitude, he repairs to the coastline in scenes reminiscent of Truffaut's "400 Blows." Every film review could, in theory, end with the thudding reminder that the film in question won't be for everyone. I suggest you take a chance on "Submarine" and find out if its particular comic angst rings any bells, be you male or be you female, Welsh or American, 16 or 61.

"Submarine"

Grade: 3 1/2 out of 4 stars

Genres: Comedy

Running Time: 97 min

MPAA Rating: R