SPOILERS! OBVIOUSLY!
I've just finished Vol 1. I'm excited and impatient and I want to watch Vol. 2 now!
But as I can't, I'm theorising 😃.
Theory 1 - Eleven won't beat Vecna / the mind flayer (is he still about?? Unclear; when the kids were doing some of their own theorising plot exposition they talked about the Demogorgon being the Mind Flayer's foot soldiers, and so Vecna is the five star general - but they might not be right?) at the end of this season. I think this will be an 'Empire Strikes Back' style plot - Eleven will leave training too soon to go rescue her friends, she won't be strong enough, and therefore set up the final showdown in S5. I reckon they've exhausted the "there's a new threat from the upside down! Ok, Eleven has beaten it, end series" format at this point.
Theory 2: related to the above. She'll need to go find Eight, the other girl who escaped Hawkins Lab, and team up to beat Vecna / whatever else is in the upside down for good. Eight clearly has the same power to create hallucinations that Henry Creel / Vecna has, Eleven has the telekinesis power. Maybe they need both to finish him off?
Theory 3: also related to the above. Henry Creel is the father of all the kids from Hawkins Lab - they all get their powers from him. Don't think he would have been old enough to be a sperm donor type situation, so am thinking maybe a form of cloning? In the Eleven's mum backstory it was said she had volunteered for the experiments but not known she was pregnant, and that's how Eleven came to be. Makes sense for just one kid, but the lab flashbacks this season have shown loads of kids - there can't have been that many accidental pregnancies!
Theory 4: Dr Brenner was actually getting Eleven to look for Creel in the upside down in season 1, not the Demogorgon. He worked out that Eleven didn't just kill Creel, she blasted him into another dimension, but as Creel was the source of the superpowered kids, and he only had Eleven left, he needed to get Creel back.
Theory 5: Steve is going to die in Vol2. Possibly saving Nancy? The Dustin / Eddie friendship is being pushed hard in Vol1, I think because Eddie will replace Steve as Dustin's big bother type figure. Also, they've killed off a lot of side characters so far (Barb, Bob, Billy) I think its time someone from the core group took a hit.
What do you reckon??