1. The sonic super power neutralizers that affected 11 and 8, but nothing else, did we see where they came from previously and I just forgot or are they new this season? Why didn't anyone think to bring in one of those to fight Henry with? I mean he showed up at the base and was slaughtering troops. Where were those disruptors? Wouldn't that make a better reason for him to leave without killing Will and why Henry stays in the Abyss as much as possible?
2. Linda Hamilton was wasted in this season. Like seriously, she won the "Cersi Lannister final season sitting around doing nothing and getting a huge paycheck for it" award. Like they didn't make her that much of evil scientist nor did they give her any character growth. She was kind of just there and if you took her out of the equation the show would have stay basically the same. A better use for her would have been that she tracked the group to the radio tower before operation beanstalk, capturing the group in the process. She finds out what is happening based on their plans. However, instead of being an evil scientist, she realizes that Henry must be stopped. She makes a deal with the group to let them go into Upside down and stop Henry if 11 promises to come back to her afterwards. It also gives you a better reason for 8 and 11 to want to die in the upside down. Also, this way you can do stuff with the army, like maybe instead of the party taking down the mind flayer, you suddenly have a squadron of helicopters coming in guns blazing. You still have the LT and his squad going rouge to injure 8, so you don't even have to change that part, and you could have had a better story.
3. Speaking of army folks, they killed a lot of US army guys in this season. I was very uncomfortable with how many soldiers got killed for doing their job. Just because they are the antagonist, doesn't make them evil fodder for our protagonists to slaughter.
4. Mike and 11 have as much Chemistry as an elementary school. Most of the time they are far apart as they can be. Like Will and Mike had more screen time together than Mike and 11. I honestly don't believe them as a couple and haven't for several seasons. They really should have spent more time on their relationship this season. It isn't like they had to cut it for screen time.
5. Speaking of relationships, Nancy/Steve/what's his face love triangle comes to a rapid unsatisfying end. While I am glad that they all stay friends and meet up every few months, I must admit that I find this to be pretty Meh for an ending for their characters. Steve coaches baseball and goes camping with Dustin, while dating every girl he can. What's his face( Jonathan? ) becoming a low budget horror film maker. Robin going somewhere? Nancy dropping out of college to go to work. A very depressing to realistic ending for my tastes.
6. No Mr. Wheeler moments in this season. You mean to tell me that this rich die hard republican Dad in the 1980s doesn't have a firearm or four? They should have had him come in blasting that Demogorgon with a 12 gauge, not a 9 iron. I love that they gave Mrs. Wheeler her moments in this season, but Mr. Wheeler should have got a bit of that too, or at least had some development over what they showed at the end. Like there is a reason that Mrs. Wheeler fell for this guy and stayed with him despite all the flirting she has done with Max's step-brother.
7. The Upside Down is now a daycare. Seriously, no demos of any kind, no hellbats, and nothing else dangerous at all in there this season, aside from one demogorgon early on that attacked a convoy. Personally, I think that was a wasted opportunity. They should have had the convoy repel the demo, that way they can say that the upside down was cleared out by the military. However, we have the same situation in the Abyss. Aside from the Mind Flayer, the party saw nothing. I do like the thought that Will killed all of the Gorgons and Mrs. Wheeler killed the last demo dogs, but I thought that we saw a gorgon putting a kid into the flayer after Will killed them.
8. What the heck is up with that ending? 8 being alive and tricking everyone was something that I saw coming a mile away. Especially considering they showed the sonic disruptors. But the whole point of everyone thinking that she is dead is that she can meet up with her family and friends later on. A better ending would have been showing the town with the water falls, then zooming in towards their post office, cutting to the inside. Showing two letters, one addressed to Hopper and the other to Mike as someone puts a stamp on each one, and they get dropped into the mail slot by a woman. She turns around and its 11. That way we can see that she is letting them know so they can all be together. I like to think that Hopper knows, as he is pretty chill 18 months later and is trying to get Joyce to move somewhere with waves. That whole scene was the best part of the ending. Hopper and Joyce finally together would be great! Having them all meet up in the end would been great.
9. Why did the military just let the party all go after the upside down was destroyed? I mean, they killed at least a dozen or two soldiers, personally stabbed the general, removed 8 from their custody, stole 11 kids from them too, and they had just shot up the base to break into the upside down. Like just because 11 was "Dead" they let them all go?
10. The next generation of D&D players. Like I didn't really like the whole passing of the torch to the younger kids moment. It felt hollow especially right after the whole party has this heartfelt depressing moment together, only for the group that is a few years younger to come down to play. Like this group of kids will never experience anything like what the original kids did. Granted they are part of the 12, but still, the magic is all gone from this world.