The stakes were very high for the 50-year-old American born and Copenhagen-based director (in fact, he celebrates his half-century birthday tomorrow), after having directed The Act of Killing (2012), a movie that subverted the foundations of documentary-making and changed the history of film. This is the first time he makes a fiction feature, and with Tilda Swinton as co-producer and star, and funding from seven developed nations on both sides of the Atlantic (including a whopping €480,000 from Eurimages alone), surely nothing could go wrong, right? Wrong. The End is over-bloated, conceited, paralysingly boring, and jaw-droppingly disappointing.

A small family lives in an underground bunker in a post-apocalyptical world. The brief mention of Salem suggests that was once American soil. The residence is plush and opulent, decorated with classic and modern paintings, and the type of expensive furniture you’d only find in the house of the filthy rich. Every piece of cutlery is immaculate, every cushion puffed to perfection. The members of the family are equally extravagant. The elegant Mother (Swinton) dons the perfect wig, yet it’s the dapper Father (Michael Shannon) who is most fond of make-up. Twenty-something-year-old Son (George MacKay) is far less vain and cocky, perhaps because he’s never experienced society firsthand. That’s because they have been locked for 20 years, since some unspecified event wiped the face of the Earth clean (there is a suggestion that the blame for the disaster might lie with the flamboyant family).

It’s not entirely clear how they keep track of days and years, since no sunlight reaches their bizarre home. The only connection to the outside world are large cavernous corridors and rocky formations, covered with white dust. It looks like an underground salt mine, however the real nature of the geology is never revealed. It is in this cold and bleak environment that the various these people experience sudden moments of redemption, for no apparent reason. A small groups of friends and associates helps the cosy family to keep the facilities running. One of such people is a Woman (Bronagh Gallagher) who abandoned her drug-addicted son lest the wreaks havoc in the self-contained environment. The precise function of these characters is never entirely clear. Nobody knows who does the dishes, the ironing and keep the sumptuous bunker immaculately tidy and squeaky clean. Occasionally the household carries out an emergency training – some sort of post-apocalyptical fire drill. A young outsider (Moses Ingram) forces herself into the gang, after leaving her own family to perish outside. A last-minute, strange addition to the eccentric underground family: she is the only black character.

During an interminable 148 minutes (nearly two and a half hours), these characters contemplate and regret their past actions, and tirelessly analyse their parasitical relationship to one another. Turgid and meaningless platitudes about life and humanity. The End focuses on the exuberant colours and textures of the residence, the costumes and the cave system, relegating the fatuous conversations to the background. Is this a comment on favouritism, elitism, race, unhinged development or perhaps nuclear ambitions? I have absolutely no idea.

To make things even worse, Oppenheimer decided to turn his film into a semi-musical. The characters randomly break into singing and then back into talking. Swinton and MacKay deliver strong renditions, with a powerful warble (I have no idea whether they were ghost-singed). The problem is that the acts are neither catchy nor meaningful. There is not one passage, one line that touched and stayed with me. I doubt that the soundtrack will be a bestseller. The End is not alone in its attempt to inject semi-diegetic singing into parts of a very long film: Emilia Perez (Jacques Audiard) and Joker: Folie a Deux (Todd Phillips) did precisely the same earlier this year, to far more convincing results.

Joshua Oppenheimer’s latest creation possesses a touch of Wes Anderson’s wacky idiosyncrasies (the robotic, self-righteous characters and the hackneyed line delivery, flirting with deadpan), as well as dash of Dogtooth‘s (Yorgos Lanthimos, 2009) confinement paranoia (minus the sexual deviation). Let’s just hope the bright filmmaker gives up his “weird” auter ambitions and instead returns to the craft he once mastered: making real people reenact real actions. Or try something else. The Act of Killing and its 2014 counterpart The Look of Silence were a hit in the bull’s eye. The End is a misfire.

The End premiered in the Official Competition of the 72nd San Sebastian International Film Festival, when this piece was originally written. The UK premiere takes place in October as part of the 68th BFI London Film Festival