Cliff chauffeurs Rick home to his fancy apartment in the Hollywood Hills. New neighbors Roman Polanski and his wife Sharon Tate, renting the house next door, zoom by in a convertible, on their way to a wild party at the Playboy mansion. Lamenting that he’s never met them, Rick says, “I could be one pool party away from starring in a Polanski film.” Fishtailing his little car through hairpin turns at high speed, Cliff goes home to a rust-bucket trailer on the fringe of a Van Nuys drive-in movie parking lot, with an oil well pumping in the dusty front yard.

Tarantino’s Los Angeles day or night is the atmospheric, noirish paradise that lives in the mind’s eye of every movie lover; sunshine by day and neon-lit movie marquees by night. His obsessive super-fandom manifests in parodies of films and TV shows, posters, lobby cards, and lingering shots of 35mm film cans and movie houses.

At one point, Sharon Tate (Margot Robbie) is seen admiring her name on the marquee for “The Wrecking Crew,” before going in to get a ticket. True to Tarantino’s expressed horror for the industry transition to digital projection, “Once Upon a Time ... in Hollywood” was shot in 35mm, which was the industry standard in 1969, and for decades after.

Meanwhile Rick takes a new acting job for a studio Western, and it seems as if Tarantino and DiCaprio are having just a little too much fun at our expense. These extended sequences of the kidnapper villain flubbing his lines and hamming it up seem more in-joke than exposition. Cliff, persona non grata to the studio stunt coordinator, gets briefly reinstated, only to pick a fight with Bruce Lee’s Kato. It’s an utterly gratuitous laugh-out-loud sequence with a bang-up finale.

The plot in this almost three-hour film is heading for a showdown with history, although not quite. More like bizarro Tarantino-style history. Cliff has a car-window flirtation with gamine Manson girl Pussycat, while driving Rick’s big white Cadillac coup deville. A visit to the Spahn Movie Ranch at Pussy’s insistence injects a spooky sense of dread that will have a haunting return, but also gives Cliff yet another chance for a satisfying down and dirty brawl.