I took a whole week to watch all of season 2 cause I wanted to make something great last. Glad I did.
My reaction is happiness. The main plot was resolved in a way that satisfied me. So did several of the subplots. Oh, and I did NOT feel that the ending dragged on too long. I want more time with these people. Which is why I'm happy there'll be another season.
We can't know what the Duffer brothers have in store for us. I think a few things are clear. The big threat from season 2 is over. But the Upside Down is still there, and is likely to have other threats. And not just threats. Maybe there are good things there, too. Don't know what. Maybe people of some kind besides animals?
The government may have been reduced as a threat, as the end of S2 suggests. But they will not have forgotten the Down Under. Or Eleven/Jane. Maybe the government agencies will be sneakier, but they'll be back. And if US government, maybe agents of other governments. The Russians, likely. But maybe Israelis? British? French?
Another possibility. We now know there was one other experimental subject: Eight. And if one other, maybe two? Or more?
Lots of possibilities, including the new characters introduced. I'm partial to Max; love redheads. And she's a gamer. (And maybe will be a hacker?) And surly Billy, her half-brother. Hate his guts, but he has possibilities too.