The first hour had me kind of exhausted with everything. As much as I never wanted Steve to die, the fakeout in the beginning with the long cut to black had me rolling my eyes. It was so cheap, almost like they were winking at us "You guys didn't think we'd ACTUALLY kill Steve, do you?" The fact that every major character survived is such a copout for this show. Like, yeah, not everything has to be Game of Thrones or The Walking Dead but for a show like this to have all the main players survive was an odd choice. It wouldn't have had to be a character that everyone liked, either. How Murray survived the whole show blows my mind. But Kali died, I guess. So there's that.
I liked the return of the Mind Flayer but I did laugh at first that Joyce got to deliver the killing blow on Vecna. Like they remembered that Winona Ryder was around. But then she delivered that f-bomb and it's like I was watching Heathers again.
I did really like the second hour or so after Eleven's "sacrifice". Which, I thought at least Millie Bobby Brown gave her first decent performance all season when saying goodbye to Mike. I didn't shed any tears over her "death" because I was sensing it could be another fakeout and sure enough...but this is one I didn't mind. Let Eleven have peace.
But the real meat was the 1989 flash forward. I'm just happy the one part of the show to take place after I was born was good. Also it was at least nice to see the younger actors playing closer to their own ages, even if it was only for an hour.

I liked Dustin's speech, but it would have been better if the Principal was this antagonist they'd been dealing with the whole show. Instead it was like "Who's this guy?" Robin crying on the roof got me, as did the end of the group's DnD game. I really liked where each character ended up.
And appropriately, since there were a bunch of endings we got a Return of the King-style animated credits scene. I knew something like that was coming when the opening credits rolled without, well, credits.
One big criticism I have about it was characters disappearing. Where was Robin's girlfriend in the epilogue? They bothered to bring her into the Upside Down and Will's coming out group but she just straight up didn't even get a mention as to what happened to here. Second was Linda Hamilton. Why was there no closure at all there? It's a little more than just "oh, they went away when the Upside Down disappeared." You're telling me there was no time for that?
Stranger Things 5 had a couple of lows but the highs were high. The Will reveal at the end of episode 4, Max waking up, and the second half of the finale were among the best parts of the series for me. None of the later seasons ever recaptured that magic of the first season but it was a fun ride overall.