The first episode does a great job of giving the viewer a mysterious background of a main character. It introduces more complex emotional and social challenges for many of the main characters to face in a way that feels natural to the story. Finally, we clearly see that there is a new, terrifying threat in Hopkins, and it's a monster that seemingly has no connection to any other monster the group has faced before.

When I watched Season 1 again last month, I was shocked at how good it was. It's no surprise the series caught the attention of the world. The villain was a horrific monster with origins outside of our world, and he posed a real threat to the group.

Season 2, in contrast, was so bad that if Netflix had been in its current financial state when it was released, it might have been the last season of the series. It's really surprising how much they "got away with" in Season 2. The main villain was literally a cloud of smoke, which is not an exciting villain type at all. Worse, the main boss from the first season returned as a normal enemy type in the second season, only in a weaker, less threatening form. It would be like replacing the T-Rex from Jurassic Park with a thousand Little Foots from The Land Before Time. One of the best scenes in the second season was when Samwise had to navigate his way through the lab using only radio guidance from the professor, and after all the tension there was no payoff. The worst part of Season 2 was just that it had no clear direction for the audience. The audience never knew what was going on at all, or whether we should even be scared of anything. I think it took until halfway through the nine-episode season for us to realize "who" the bad guy was.

Season 3 fixed all of that, mostly. They introduced the main villains in the first episode, giving the audience a clear definition of what the whole thing was going to be about. They also lightened up the tone and made it more of an action adventure show than a horror show. My main complaint about Season 3 was that the villain was the same villain from Season 2, and even Season 1, by extension. Although the Mind Flayer from Season 3 was given a new, more terrifying form compared to being literally dust in the previous season, he was still the same guy with the same general powers and weaknesses from Season 2. They even defeated him in the same exact way.

Season 4 is starting off as strong as Season 3 did, but even better in some aspects. First, we know who the villain is right away. And he's terrifying. He's genuinely scary, and I actually felt that I was watching a horror movie at the end of the first episode. Second, the villain is - at least as far as I know so far - entirely new. He's not just "The Mind Flayer 3.0" or another spinoff of the Demigorgon. Even stranger, he seems to predate the known existence of the Upside Down. Perhaps he was the original creator of it? Or perhaps what we've seen of the Upside Down in this season so far isn't even the Upside Down? No one knows, and that's what makes him scary.