I thought it was mostly great, with the Hawkins story line being so much better than anything else. The Russia stuff was okay-ish mostly because I liked the characters, but everything in California was a mess outside of Pizza guy.
I do feel like the are getting increasingly cowardly with the writing, coming up with more and more convoluted ways to be like "no this core cast character" isn't dead and instead killing off the one season side character instead. Hopper is the worst still, but Max this year was bad as well. I look forward to whatever character they introduce episode 1 next season dying in the finale instead of anyone of actual importance.
Also, I get that everyone likes Steve and they want him to end with a love interest, but man they could not make Jonathan any less likable. He has one good scene where he's basically like "hey man it's ok" to his brother and then he's just an absolute charisma void the rest of the season. Not that anyone in that whole plotline was any good but he stands out as somehow the least likable of this crew of unlikable characters.
Again, though, complaints aside, Hawkins saved it for me this season and I think this is very close to my favorite season of the four. If they had killed Max in that first Vecna interaction, I think that would've been an all time top tv scene for me.
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Moops? "I thought you were making up diseases? That's spontaneous dental hydroplosion."