Were it not for a single scene in which 14-year-old Duncan (Liam James) is caught listening to an iPod, it would be tough to identify The Way, Way Back as a contemporary comedy. Everything about the film feels gently nostalgic – to the early-to-mid 1980s, to be precise, a time of Pac Man games and REO Speedwagon, and probably the last era when the highways would be routinely populated by the 1970 Buick station wagon that provides the movie with its title.

That era likely struck a chord with writer-directors Jim Rash and Nat Faxon, here making their directorial debuts after winning a Best Screenplay Oscar for 2011’s The Descendants. But it’s not an ’80s sentimentality that makes The Way, Way Back work – rather, it’s a nostalgia for childhood in general, combined with an adult’s generous perspective on just how unfair and painful that adolescent time can be … even on summer vacation.

The film opens on Duncan, sitting sadly in the Buick’s “way way back” seat. He’s being dragged by his mom (Toni Collette) to the Cape Cod vacation cabin of Trent (Steve Carell), her insensitive creep of a boyfriend. (Carell’s stretch into unlikeable territory is one of the film’s bravest moves – it’s the first time he’s ever played the true villain of a story.) Duncan hates Trent, and doesn’t want to be trapped among partying adults and indifferent teens for the summer. So he mopes, until he finds a tiny refuge at the water park across town – and in the company of Owen (Sam Rockwell), the wisecracking park manager.

Within the confines of the Water Wizz park, Duncan begins to come out of his shell – and attracts the attention of Susanna (AnnaSophia Robb), his next-door neighbor who’s only slightly less unhappy on vacation than he is. Suddenly, things are looking up for our hero.

The Water Wizz sequences provide a warmth and gentle humor that nicely offset the acrid pain of Duncan’s experiences back at the shore with Trent and his mom. Much of that is due to Rockwell, whose rat-a-tat one-liners and kind mentorship of Duncan are sharply reminiscent of Bill Murray’s role in Meatballs – another ’80s reference. Rash and Faxon play small but memorable roles as water park employees, as does former “Saturday Night Live” veteran Maya Rudolph.

This strong ensemble cast is anchored by James’ powerful turn as Duncan, a kid quietly seething with adult-scale frustration – but still convincingly just a kid, who’s looking for a place to belong. The Way, Way Back isn’t revolutionary filmmaking, but its deft presentation of Duncan’s world feels like a big victory for small movies everywhere.

The Way, Way Back. Starring Liam James, Steve Carell, AnnaSophia Robb and Sam Rockwell. Written and directed by Nat Faxon and Jim Rash. Rated PG-13 (guidance strongly suggested for children under 13), for mild language, mild sexual content and drug use. Rating: 9 out of 10