It’s the “last day in paradise” for Las Vegas dive bar the Roaring ’20s, which will shut permanently after the evening’s festivities. Over the next 18 hours, as the booze begins to flow, there are several slurred flirtations and a fight. Inevitably, at least one person takes their top off.

The film is directed by Bill and Turner Ross (known for their documentaries 45365 and Tchoupitoulas), and shot fly-on-the-wall style. But elements of this riotous hybrid documentary are staged. The Roaring ’20s is actually in New Orleans, not Vegas, with characters street-cast, and playing fictionalised versions of themselves. Yet the sense of the watering hole as a haven for lost souls – not to mention the threat of gentrification to civic space – couldn’t be more vérité.

Inside the bar, red fairylights give a rose-tinted glow. The film’s mood is bittersweet, never more so than in a scene that shows the revellers trailing into the car park to set off fireworks, depicted via grainy security camera footage. Sophie B Hawkins’s 1992 track Damn, I Wish I Was Your Lover (a pop song about bearing witness to an abusive relationship) plays softly from the jukebox inside. Martin, a regular, hovers by the bar, watching Hollywood western The Misfits. Like Eli Wallach’s Guido, whose voice can be heard on the TV, he’s “just looking for a place to hide and watch it all go by”.