The Good: I think the thing I really loved about this episode was the humanity of the relationship between Steve and Nancy. It’s a classic case of people being truly out of their depth, and taking it out on one another. The guilt Nancy feels about her role in Barb’s death, having essentially shoved her lonely friend outside to be eaten by the Demogorgon is understandably significant, if misplaced. It’s not, after all, as though she knew (or could have known) that there was a Barb-eating monster around. Barb herself could have saved her life by just getting in her car and going home. But that’s the way people think. It’s tearing her up, and she wants to tell Barb’s parents (who are still looking for their daughter and spending their life savings doing so) the truth.
When she confronts Steve about this, he quite reasonably points out that talking about what they know is likely to a) get them in a lot of trouble with the government and b) not really help, because after all, what are they going to tell Barb’s parents? “We know your daughter’s dead because she was taken into a parallel dimension by a monster we both fought and our psychic friend who disappeared told us she died?” No parent with any sense would believe such a thing.
Factually, Steve is right. Emotionally, he’s completely wrong, but it’s expecting a lot of an 18 year-old to successfully navigate the right response to his traumatized  17 year-old girlfriend, just as it would be asking a lot of Nancy not to blame Steve for his unhelpfulness. Neither of them are bad people, but they are acting in a very human way, which destroys them as a couple when Nancy finally lets the blame out all over herself and Steve.
Also, it was good to get the backstory on how El ended up with Hopper.

The Bad: There wasn’t much bad about this, except for Hopper’s real lack of understanding what he’s doing to El by keeping her in a state of permanent cabin fever. But again, he’s dealing with his own shit, obsessed with saving a girl that he can to make up for the daughter he couldn’t.

Further Questions: Not many in this episode except for what is that thing Will keeps seeing that looks like Great Cthulhu?