There’s one obvious metaphor that I dare say playwright turned filmmaker Stephen Karam couldn’t make nearly as obvious in his play, “The Humans,” when it was on the stage. But it stands out like a scarlet letter in his intimate, warm and mournful film of the piece.

Everywhere we look in this “new” apartment daughter Brigid has moved into, evidence of its pre-World War II Chinatown provenance stands out.

He shows us closeups of plaster that has aged, moistened and blistered. The doorways show decades of wear. The windows haven’t been caulked since the Eisenhower Administration. The antiquated light fixtures are popping bulbs, left and right.

And everything, from the ancient radiator to the leaky, rust-stained pipes, has been painted over, time and again, layer upon layer of surface added to something that needs to be addressed, fixed or at least talked about in the open.

“The Humans” is a moody, talky family-get-together melodrama that surfs a sea of banter as the parents, grandmother and sister of Brigid (Beanie Feldstein) come to eat, drink and house-warm the two-story flat that she and student-boyfriend Richard (Steven Yuen) have just taken on. Will they get at what’s going on beneath the surface?

It’s a film of overheard snatches of conversations. Dreams and problems and issues discussed and listened in on, sometimes barely made-out two muffled rooms away. Conversations are often interrupted by the hustle and prep of a big meal in a place with little furniture, noisy thunking pipes and a noisier thumping neighbor.

The hallway is almost too narrow for Erik (Richard Jenkins) to get his mother, “Momo” (June Squibb) in the door. In an instant, we can see how overwhelmed he and wife Deirdre (Jayne Houdyshell) are dealing with a 90ish woman mumbling from dementia. And that’s before we hear some of that mumbling, or how expensive it is to keep them with her.

The Catholic parents are here to hang out with the unmarried couple and with their daughter Aimee (Amy Schumer), have a little fellowship, celebrate the new home and catch up.

Erik is Mister Gloom and Doom about the “flood zone” they’ve moved into, advising Richard to “save now,” before he and Brigid get married, before they face the expenses that accumulate AFTER the college loans come due. Erik is practical and handy, checking the fuse box, eyeballing the plumbing, suggesting “hard work” as a solution to most problems. He’s worked at a pricey Catholic school forever, in maintenance and cleaning.

“You don’t pick up after other people’s kids for 28 years unless you really love your own,” he says, mostly for Richard’s benefit. His daughters got free tuition there, and a head start in life. Aimee’s a lawyer living in Philly. Brigid’s a New York composer hoping to make her mark in orchestral music.

Deirdre is just as working class, marveling at Richard’s frank discussion of his mental health, something Erik insists “nobody in our family” has problems with.

Nooo, Deirdre says. “We just have a lot of stoic sadness.”

A lot of what’s said over the course of this evening is translated, explained for Richard’s benefit — family “traditions,” the status of a long-planned “lake house” Erik and Deirdre hope to retire to, what Momo was like before her final break with reality and the various elements of sibling bonding/rivalry that the sisters have acted out.

The word “judgement” gets tossed about. Faith is preached as “a natural anti-depressant,” and lightly mocked. The merits of being “unhappy alone or unhappy with someone else” are debated. Richard struggles to manage sports small talk and not give away every “issue” he’s dealing with, and not have Brigid give those away for him.

Health problems, jobs lost or soon-to-be-lost, financial strains, the frustration of this or that career that isn’t taking off any time soon, all come up, almost buried in the banter.

And Aimee? She’s in the noisy, ancient toilet, not just for her ulcerative colitis. She’s on her cell with the longtime-love that she just broke up with. Something’s bound to break, something beyond the wiring and the plumbing.

The great character actor Jenkins has perfected his blue collar guise, adding to the collection of professionals, authority figures and scientists he’s played over the years. Erik’s fatalism has come from age, a lifetime of caution and fear about the future.

Eventually, “everything you have, goes.”

The other stand-out in this cast is Schumer, whose character’s many problems make us wonder how she is keeping it all together. Aimee’s physical issues cannot help but make us fret over what Schumer’s been telling us about her own health in recent years. Aimee the character and Amy the character actress aren’t shy about flippantly sharing medical problems with those who love her. But one look at Aimee makes us wonder what she’s not telling us.

Whatever everybody else has going on, none of the characters save for hers made me feel anything about their plight.

Karam’s film doesn’t “open up” the play so much as absorb us into its claustrophobia. But “The Humans” feels so unsubtle and “theatrical” that when the story makes its third-act turn towards BIGGER REVELATIONS, it feels abrupt and melodramatic, like a script outline that dictates “Third Act Surprise comes here.” It’s as obvious as “granny’s one sentient moment,” which we know is coming and can only hope won’t be cloying. It isn’t.

There’s so much messiness in these lives that the film feels universal, thanks to the viewer’s experience of the world and the realization that “everybody’s going through something.” The cast is skilled and accomplished, but some characters and their problems are barely sketched in, while others are magnified by the old “blurt my problems out in the third act” trick.

The only “issues” that feel lived-in are the ones literally everybody faces — health, aging parents and grandparents — mortality. It’s the players most wrapped up in those who stand out. The rest is just colorful, sometimes flippant, background noise.

Rating: R, language (profanity)

Cast: Richard Jenkins, Amy Schumer, Beanie Feldstein, Steven Yuen, Jayne Houdyshell and June Squibb.

Credits: Scripted and directed by Stephen Karam, based on his play. An A24 release.

Running time: 1:48