There are really good recaps all over, so I only review.
Acting: Harbour is on point this episode; try to imagine how hard it would be to act like you're acting, re-watch that diner scene, and get back to me. He was great. Ryder did a good job of doing the Roy Neary arc of appearing crazy while being aware of more than others. Joe Chrest looks like he might get to be more than 'the dad too tired from work to notice the little things', which is good because he's a solid actor. And, with feeling, Cara Buono is surprising me with her very consistent portrayal.
Millie Brown keeps doing a lot with a little. Charlie Heaton is actually getting a chance to act and is doing well. Joe Keery put in a journeyman performance and Natalia Dyer keeps letting me down. Watch the scene between Nancy and Steve in the side alley at school; Keery is pretty good. Dyer is using the same performance as when Barb wanted to leave the party.
Cinematography: Drom now on I think I'll just mention when it is NOT great. Tod Campbell did a great job; he had shout-outs to the Searchers and Stagecoach in his use of cameras and I freakin' approve.
Editing: Well, that got better. Hmmm. Episode 1 and episode 4 were edited by Zimmerman, eps 2 & 3 by Ross. I think it is obvious I prefer Zimmerman's editing style and I shouldn't blame the director.
Directing: Like Ross v. Zimmerman, I am quickly concluding that the Duffers are very good at directing child actors and Levy isn't. Which is weird because Levy started out directing shows like The Famous Jett Jackson, etc., and you'd think he'd be good. But the young actors just seem much more unnatural under Levy than under the Duffers. Perhaps he is used to the over-the-top style of shows aimed at pre-teens?
Characters: As much grief as I have been giving Natalia Dyer, let's be honest - Nancy is a character with really uneven writing behind her. She spends all of one and parts of 2 episodes lying about what she and Barb were doing, where they were, etc. and she is mad that Steve doesn't want her to mention underage drinking? She lied about a lot more for reasons that don't involve possible jail time.
The younger kids are coming along, but I find the characterization of Lucas still annoys me. He continues t act like a bully and as an unlikeable sort. Dr. Brenner is nicely enigmatic. I also hope that with Eleven we can transition from flashbacks to actual, you know, character development.
Yes, the treatment/development of characters is contemporary. Sure. But since Stranger Things is not of the time but rather is about the time I have no issue with it. I think of it this way; character development in Stagecoach is different than in Per Un Pugno di Dollari, yet both are set in about the same time period. Both are fine films, too.
Story: I can forgive a lot because the underlying story is above average for today. One thing the Fun Lads Four mentioned is that so far the story is about as good as an average Champions/Top Secret game which is a bonus because most science fiction/horror these days gets nowhere close to as good as an average campaign (I'm looking at you, Firefly). The sub-plot with the guy going into the Far Realm (see what I did there?) in a harness was utterly predictable but still interesting because the writing, acting, cinematography, and directing were good. The bit of El being able to do remote viewing and broadcasting the results is inspired because now we don't need to have a character pull a Deanna Troi and go into long monologues about what people feel and think. It also ties in the electrical phenomena and the idea that maybe El isn't using mental powers but something else, something a lot... stranger.
Oh - and I loved the shout-out to Scanners.
The reveal that Will's body isn't even a body was great. The arc with Hopper has got that paranoid late-70's/early-80's conspiracy theory movie feel to it, like Blue Thunder and Capricorn One.
Final: It feels like things are getting back on track. I hope the Lucas character is reeled in soon, but I fear he's going to go even more confrontational, maybe even physical. The actions at the lab are going to be critical and I suspect that Hopper is going the path of films where he can't trust anyone but those everyone else thinks are crazy.
It is obvious that a protagonist is going through a gate sometime soon, maybe against their will. Based on the lights and the radio, maybe the monster is vulnerable to electricity.
See you soon!