Lots has been said about Tarantino's newest film, and I don't pretend I have something entirely new to say about it. I enjoyed the film, but two weeks after seeing it I notice I don't really remember much about it. This is a totally different reaction from Reservoir Dogs (which, admittedly, I saw three times in a row) or Pulp Fiction or even Django, which I enjoyed a great deal, though I had given up on Tarantino after being bored watching Kill Bill (which I haven't rewatched).
But I keep thinking about the new film. There's something I can't quite put my finger on. The narrative is very loose, there really is no plot (I think this is something people who didn't like the film are complaining about) and there are scenes that don't usher the story on. The ending has also been criticized, a friend of mine said it was an adolescent fantasy. To me it was possibly the point of the whole film. As everyone probably knows already, the Sharon Tate murders don't take place in the world of Tarantino's film. This is because Brad Pitt kills Charles Manson's cronies in a frenzied battle after they've gone to a wrong house! Shortly before we've witnessed Sharon Tate watching her film (the Matt Helm vehicle The Wrecking Crew) in a state of happiness and joy. The magic of cinema is so strong that it can even give you the world where Sharon Tate was not killed! This is pure poetry to me, and a proof that Tarantino really loves cinema and is not simply a movie buff showing off.
Or then the ending scene could be fiction, imagination. Just before Manson's killers enter the house, Pitt drops some acid. I think it's entirely plausible to say that Pitt just imagined the whole thing. It might also explain the weird scene with Bruce Lee.
I was also thinking about the films that are being watched or are visible in other ways, i.e. as posters on the wall. Almost none of them seem to be very good (for example, The Wrecking Crew), but it seems to me Tarantino has affinity towards all of them. See these links: Ten films you need to see to appreciate Once Upon a Time in... Hollywood and Tarantino's curated list of the films to go with OUATIH. This is a work of true love.