Sasquatch Sunset review – brilliant bigfoot oddity is unexpectedly moving

<span>‘Gloriously weird’: Jesse Eisenberg in Sasquatch Sunset.</span><span>Photograph: AP</span>
‘Gloriously weird’: Jesse Eisenberg in Sasquatch Sunset.Photograph: AP

It might be one of the finest pieces of acting of the year so far. Near the end of Sasquatch Sunset, the gloriously weird feature from David and Nathan Zellner, Riley Keough wordlessly conveys a slowly creeping moment of profound existential despair that crushes your heart with its bleakness. It’s all the more impressive that she achieves this using her eyes alone, since her face and body are encased in a thick prosthetic layer of foam and straggly fake hair.

Keough plays one of the family of four sasquatches (the mythical creature also known as bigfoot) that the film follows over the course of a year as the primitive, grunting ape-like creatures lumber through the forests of the Pacific north-west of America. It’s an extraordinary film, an entirely singular creative venture. You won’t have seen anything quite like it before. It’s quite possible that you would prefer not to watch anything quite like it ever again. But for anyone who is intrigued by the idea of a movie that serves as both a treatise on despair and loneliness, and a delivery vehicle for extravagantly crass toilet humour, weaponised faeces, absurd sight gags and some rather bracing sexual encounters, this rather wonderful oddity ticks all the boxes.

You half expect the feathery tones of David Attenborough to accompany the sasquatches silhouetted against the horizon

Of course, we have to take it on trust that it is Riley Keough delivering this wrenching performance. She and co-stars Jesse Eisenberg, Christophe Zajac-Denek and Nathan Zellner (doing double duty in front of the camera as well as behind) are unrecognisable beneath their body costumes and a layer of facial makeup and prostheses that reportedly took around two hours to apply each morning. At first, there’s something almost disconcertingly crude about the sasquatch skins. They seem a little unsettling and artificial, like a kind of full-body merkin that might have been cobbled together from the contents of a waxing parlour’s bins – all wispy errant hairs and inert rubbery flesh. But in just a few minutes, thanks to the persuasive physicality of the performances, you stop seeing the costumes and start engaging with the distinct, if rather basic, personalities of each of these hirsute humanoid creatures.

Zellner plays the alpha male: aggressive, posturing, dominant and driven by base appetites and urges, for sustenance and for sex. And yes, we do get several glimpses of priapic full-frontal male sasquatch nudity, in case you were wondering. The alpha is the risk-taker of the troop. While the others nibble cautiously on bracken leaves and cape gooseberries, he greedily chows down on mouldy, semi-fermented soft fruits and fly agaric mushrooms, with unfortunate and entirely predictable consequences. Eisenberg, as the subordinate male of the group, plays his sasquatch as a dreamer fascinated by the world around him. He has the rudimentary beginnings of an empirical brain, and is driven to quantify the things that he sees. Unfortunately, this urge is rather limited by the fact that he can’t get his head around any number greater than three. Zajac-Denek plays the child of the clan, and Keough is the only female sasquatch. She’s the feistiest of the group, emphatically rebuffing the romantic advances of the males. But increasingly there’s a weariness in her demeanour, a bone-tired resignation that comes from being the only halfway competent caregiver in the little family.

There’s no sasquatch language, beyond a series of grunts, whoops and whistles. But the clan regularly attempts to communicate with others of their kind, beating out a rhythm on trees and waiting, hopefully and vainly, for an answer – it’s a repeated motif that becomes increasingly poignant each time the ritual is performed.

It’s not the first time that the Zellners have ventured into the world of the sasquatch – the directors, who describe themselves as bigfoot fans from childhood, made a short film titled Sasquatch Birth Journal 2, which screened at Sundance in 2011. Subsequently, the defiantly oddball directing team became known for their picaresque anti-quest stories. Kumiko, the Treasure Hunter follows a depressed Tokyo office worker as she seeks the bounty from the Coen brothers’ fictional crime film Fargo, a stash of money that she believes was hidden, in real life, somewhere in North Dakota. And Damsel takes a gormless Robert Pattinson, with a stumpy miniature horse in tow, on a journey across the old west.

Related: Kumiko, the Treasure Hunter review – quietly magnificent

Even by Zellner standards, Sasquatch Sunset is an eccentric picture, near plotless, frequently hilarious (a scene in which the sasquatches encounter a road is as pure and perfect a moment of physical comedy as I’ve seen in a long time) and shot with the loving reverence of a prestige BBC wildlife series. You half expect the feathery tones of David Attenborough to accompany the arrestingly beautiful widescreen shots of the plodding sasquatches silhouetted against the horizon. But what the film shares with the Zellners’ previous pictures is a deft handling of tonal shifts, particularly the delicate tipping point at which flippant absurdity gives way to the darker minor key of melancholy. Who knew that a film containing this much gratuitous arse-scratching could ultimately be so heartbreaking?

• In UK and Irish cinemas now