The Shins-sounding score, courtesy of Fall On Your Sword, lets us know we're squarely in hipsterville (Silver Lake to be exact), where the already delicate balance of family dynamics within a fabulous sun-lit crib is about to be pushed over the edge by a new arrival. There's trouble in paradise when therapist Julie (Rosemarie DeWitt), has her sound designer husband Peter (John Krasinski) agree to help 23-year-old friend-of-a-friend Martine finish the sound on her full-of-itself gallery installation, drawing grungy black and white parallels between ants and humans so guileless, it's as if the connection's never be made before.

After firmly establishing the project's pretentiousness, the reasons for intercutting footage of ants (personified with irksome Miranda July-style voiceover), throughout the film fails to illuminate or comment on the drama in any meaningful way. Reaching for vague correlations between the head-down focus of the ants and the solipsism of the small circles the privileged run in, this artless stylistic device is laughably at odds with the subject matter. As for the film itself, you wonder what gallery owner in their right mind would commission a half-baked A.V. Club assignment for the scrutiny of the New York glitterati. For a brief moment there's the possibility that Russo Young is being inconspicuously satirical, until Martine starts talking in red-faced earnestness about the sound of an ant's heartbeat being akin to the sound of heartache.

It's such a shame there is no bottom to the ways in which Martine's ditzy cluelesness quickly begins to irritate, given the strength of her introduction. The calamity this reckless free spirit will wreck upon the family home is established with playful economy in the film's opening. Martine is seen getting hot and heavy in an airport cark park – presumably with her boyfriend – until she stops to say how she really enjoyed meeting him on the flight, but not quite enough to think twice about dismissing him mid-grope.

Set up as edgy and fierce, Martine turns out to be an insecure easy lay, self-absorbed to the point of complete inarticulation. "I mean, like, um, like, um, you're not sitting in your fear" is one pedantic nonsensical piece of direction she gives to a voiceover actor, understandably pissed off at having to do endless takes of throwaway lines.

Taken in by a family she's never met, not paying a penny for ample time spent with an upcoming sound designer who's just starting work on his first Hollywood feature and granted access to gear and actors she could never afford otherwise, the lucky break of this golden opportunity seems to have completely escaped Martine, who for all her prostrations about the seriousness of her work every time she's sidetracked by a casual fling, can't even be bothered to show up at the studio on time the one day she's working with actors. Everything is handed to her on a silver platter and somehow the film expects us to care about her first world problems as she thoughtlessly pisses it all away.

Apparently, Martine's 'artistic vision' is enough to revitalize Peter's passion for sound design, sapped by the mindless grind of working on a blockbuster. I'm sorry, but if I were just starting working on my first big, commercial film, I'd be bouncing off the walls. Yes, these enterprises are often soul-sucking, but no matter the quality of the material, every newbie working at that level for the first time has at least a few pictures in them before they become so insufferably jaded. Being artistically true to himself (and to Martine's delight), Peter then goes about slathering the film in synth. If sub-John Carpenter sound fields are any indication of his untethered imagination, he clearly won't last long in Tinsletown and creatively, he and Martine deserve each other.

You see, Peter, despite being a happily married man who gets on great with the two kids from his wife's previous marriage, can't help but be drawn to Martine and her manic pixie haircut. Though the film keeps telling us he's found a kindred spirit in this exciting young artist, the only reason anyone with a modicum of taste and common sense might sit there and fawn over such shallow-end experimental guff is because they're desperate to jump her bones. And Martine is attractive. Distractingly and annoyingly so. Her choppy, sassy haircut, fashion-model-just-rolled-out-of-bed look and mega-watt smile of a thousand gleaming white teeth that could blind from ten paces is an insufferable combination of genetic good fortune out of proportion with her dim-witted naivety. Chris Blauvelt's cinematography not only makes these people's lifestyle desirable but their looks too, and despite his giant schnoz, for the first time, everyman Krasinski is every inch the movie star. All day-at-the-beach quiff and three day stubble. Living this well and looking this good is a definite distancer from people already living on Planet Me – not satisfied with his huge swimming pool, Peter is overheard moaning about Julie's ex (Dylan McDermott) not paying the child support that would afford them the extra luxury of a hot tub.

Their character's heads may be in the clouds but the awkward sexual chemistry between Thirlby and Krasinski sizzles excruciatingly in that way that most mumblecore can only dream of. The punctuation of pained silence is easy to do but rarely this loaded. The situational aspect slyly exacerbates the tension: watching Peter undress Martine with his eyes in a soundproof booth makes his inevitable bow to temptation all the more unbearable and when it finally occurs we're treated to an insightful, smartly sequenced montage from editor John W. Walter, cutting back and forth between the lovers' silent bubble of ecstasy and the other characters outside in the real world, where there are dangerous consequences and people get hurt. If Russo Young had somehow been able to soundproof the dialogue, shooting Peter and Martine's scenes together entirely in stolen glances, she'd have been on to a winner. As they are, the scenes are undone by the unintentional hilarity of teenage diary hockiness, instantly deflating all the expertly built tension. "Being this close to you is unbearable" Peter says at one point, hitting the nail on the head.

At the root of this destructive tryst, it's interesting to note the screenplay's refreshing feminist reversal of the familiar caligynephobic dynamic. Though she sets hormones racing (even Peter's wife admits being attracted to her), as a temptress, Martine doesn't fully realize the extent of her sexual power, easily giving into male attention but never asking for it. Unpacking this presents an ideal opportunity to illicit some much-needed sympathy for Martine, but Russo Young and co-writer Lena Dunham don't take it, far more interested in using her as the catalyst for showdown scenes, giving their ensemble the chance to do lots of emoting.

As played by Rosemarie DeWitt, Julie is the one sympathetic character whose jealousy gets the better of her when she catches on to the attraction between her husband and the ingénue. As a woman refusing to acknowledge a growing rift and mounting tension before it's too late, it's a coiled, victimized portrayal and regardless of her wealth, DeWitt reminds us of the type of person we all know who enjoys being upset more than being happy but complains about it anyway. Unable to help herself from rocking the boat, not only is she the one who invites Martine into their home, but she regularly has her ex-husband round for dinner, possibly less for the sake of the kids and more for the vain entertainment of watching two men exchange verbal blows in their efforts to impress her. Julie's self-defeating efforts at playing peacekeeper make her a likeable, flawed character wasted in a superfluous subplot with an amorous patient, existing simply to mirror the main action and give the illusion of depth à la Safety Not Guaranteed. As a performer, DeWitt has an inherent decency which makes it easier to overlook Julie's good intentions and bad choices but there's no getting around some of the sick bucket "good job!' Americanisms she gets saddled with: "I'm pro hug!" she cries upon introducing herself to Martine. It's also impossible to be completely on the side of a woman who knowingly names her kids Dusty and Kolt.

Kolt (India Ennenga) is a precocious pre-teen on the verge of womanhood, introduced out in nature taking private Italian lessons in the Hollywood hills (just like my childhood then). At the center of an unnecessarily creepy plot strand involving her tutor, it's another instance of clumsily commentating on the protagonist, inferring similarities in their emotional state, despite the difference in age. When the tutors' perversion is ousted and he woundedly labels his student a pubescent prostitute, the young girl is worryingly blasé about it afterwards, able to laugh it off with Martine who encourages Kolt, calling her a 'hot' prostitute. This gravely mistaken interjection of humour as balm, skims over the scarring reality of such an outburst and if we're laughing, it's at them, not with them.

Nobody Walks largely ignores reality altogether, existing in a place that few who watch it will have experienced. Economically and dramatically, the world the characters inhabit bears little resemblance to our own, their problems and the way they self-servingly deal with them, entirely unrelatable. It's a snapshot of a culture and people that doesn't have an audience in mind.

This exclusive interview with director and co-writer Ry Russo-Young was conducted by Timothy E. RAW at the 2012 Sundance London Film Festival.