Alex Billington’s review published on Letterboxd:
As expected, Once Upon a Time in Hollywood is Tarantino referencing other films and TV and old Hollywood and good times in the 60s. Digging into his past and showing us, through perfectly crafted cinema, his feelings about moviemaking and artists and the Manson murders and more. To be completely honest I'm not yet sure what to make of Once Upon a Time in Hollywood. Need to let this one marinate, don't have an instant reaction. Most of the film is pretty good, I'm having fun watching them play around in late 60s Hollywood. Then the finale is HOLY FUCK.
I really like the film but don't love it. I need to discuss it more, and then go see it again in hopes that all the ideas hold up on a second viewing. It's definitely fun and more amusing than most of Tarantino's other films, but it's overlong and not as completely brilliant as I was hoping. Though I do love the ending.