I went and saw this on Sunday. The short of it is that I liked it. It has a bit of everything wrapped up in a whole lot of surrealism. I also liked as it was party film, as in adventuring party. You could see players rolling up those characters and forming that group.
I am not going to give any spoilers away. I didn't have a particularly hard time following the plot even with my hearing loss causing me to loose a sentence here and there. (Hearing aids help but like glasses there are limitations). Just think of levels in a Dungeons that you access by falling asleep and it all make sense. Including, I think, the final sequence.
The only part that struck a wrong note with me was a freefall segment. And it only born of my familiarity with all things space. The basic issue is that while it looked spectacular and utterly seamless the one they got wrong is when the guy positioned himself to do something. In real freefall it is extermly hard and tiring to do anything less you are using anchors like foot rests, arm loops, etc. Imagine you floating along and you grab something to stop. What happens is that your forward motion does indeed stop but your body begins to rotate around your hands. On the ISS the astronauts learns to pivot to slip their feet into an anchor so they can keep their hands free to work.
It is a very minor issue in an otherwise visually stunning sequence. I only bring it up for it's trivia value. Eugene Cernan, Michael Collins, and Richard Gordon on Gemini IX, X, and XI all suffered from this issue until NASA came up with a scheme of foot rests, rails, and arm loops that Buzz Aldrin proved out on Gemini XII.