well I finished this over the weekend and gotta say it left me disappointed. seems like they left the smart writing and twists and turns of seasons 1 and 2 and decided to go for a standard jump-scare horror series. and then they diluted it even further with the whole Russian base under small-town America thing. the whole thing just didn't grab me in the same way that seasons 1 and 2 did, and I almost found myself watching it just to get through it. to me it lacked some of what makes ST such a great show. I did like the character development but even that seemed rushed.
and there were several things that had me thinking "aww, come on, seriously?" like the Russian thing. putting aside the corrupt mayor being in cahoots with them, there was a Russian base with 10 miles of tunneling under a mall, the mall guards all talking with Russian accents, dudes running around a fourth of july fair shouting in Russian to each other, an immense amount of power being stolen from the grid, presumably a huge number of non-English speaking Russians getting ferried in, and no one noticed? the massacre at the hospital seemed to go unnoticed as well. and there were a lot of flayed that wandered off without anyone seeming too worried.
and Eleven losing her powers seemed a copout too. it was as if the writers realized they couldn't just have her saving the day again so randomly shut her down for no reason that I could see.
I also wasn't keen on the three different storylines running in parallel and not having Hopper, Dustin et al and Eleven et al involved in each others' storylines until 20 minutes from the end.
having said that there were some awesome moments in the show and if I hadn't watched seasons 1 and 2 I think I probably would have really liked it. it was a good watch just not as good as i was expecting. and the ending was super sad and had me sitting for at least 5 minutes after tryin to process it.
One other bone to pick: If I followed correctly, the Mind Flayer made a comeback because some leftover portions remained on our side of the passage to Upsidedownland when Eleven closed the portal. Yet, the key to stopping the new giant tarantula was re-closing the reopened rift?
Some bulldozer-sized chunks of TMF were left in the Starcourt Mall when the dust had settled. I don't think that the Russians need their pet demogorgon to get their program rolling again.
my understanding is that without the link to the "brain" in the upside down, the bits in our world are useless.