So, the good parts: The acting is generally on point, most of the cinematography is great, and I really liked the slow-burn approach (mostly). And taken individually, each of the three stories could have made a decent movie unto itself. But for some inexplicable reason, the producers decided to try to mesh together three storylines that have virtually nothing to do with each other - and in the process none of them is fully fleshed out.
I've read some of the glowing reviews on here, and for the life of me, I can't figure out what they're seeing that I'm not. I'm not a simpleton that needs to have every plot device explained to me; I have no problem with abstract concepts, implied relationships, or things happening off-screen in a film. But this movie is either about an ancient subterranean entity in Asia, a scary U.S. childhood legend that may have turned out to be real, or a secretive cult that has somehow been manipulating people's thoughts and/or creating people to use for its own nefarious, but undefined, purposes. It tries but fails to be about all of them at once. I tired, I tried so hard to make sense of these three disparate storylines - but finally I gave up. If the movie can't make them line up any better than it did, then why should I kill myself trying?
Intentionally obscure storytelling is not the same thing as being avant-garde. For all this movie's strengths, it cannot overcome poor plotting. You should wait until it's on some streaming service and try and decode it then, but don't pay to go see it.