In the episode where you find out Eleven's story, we had already guessed some of it. We'd said ages ago we thought the guy helping her might be One. We figured out maybe 10 minutes before it's revealed that he was also Vecna. We didn't realise he was Henry until it was said. Really liked it, I came to the conclusion that Eleven had created the upside down, or at least the Hawkins part of it, when Nancy realises her room is stuck in 1983 over there, Niall wasn't convinced until nearer the end. Not sure if that's just when the world imprinted its form on the upside down, or if Vecna deliberately did it as it was what he knows, or if it's just some random coincidence (how would he know what Nancy's room looked like?) but I'm enjoying how it all circles back round to Eleven and the experiments Papa was doing. I'm sure they said season 4 was the last one though so I suspect Vecna being burned up was meant to end with him dying then someone said "oh go on, here's more money, make his body disappear". Eddie was awesome and I'm so upset they killed him off! We're undecided as to whether Max is lost forever, is in Vecna's head or even in El's head.

Still not a huge fan of a lot of Stranger Things. The upside down certainly existed before Eleven breached into it, but it seem the further along we get in the series, the more absolutely everything revolves around her.