I absolutely loved it! Totally disagree with others that the finale didn't have enough action, it had loads - did we watch the same thing?? The friendship and camaraderie throughout was the best I've ever seen in any film or tv series ever, and I think that's what people love about it. That and the spot on 80s nostalgia which is just brilliant.
There were a couple of things that puzzled me - firstly why they didn't all end up in jail, especially Hopper, having shot and killed loads of soldiers and broken into a military facility on multiple occasions - how did they get away with that, why were they all allowed to return to their normal lives? The only thing I can think is that they were witness to so much in that military facility and could have told the world, but they probably wouldn't have been believed anyway. And where did all the pregnant women with their scientifically altered unborn babies go? Why wasn't Erica arrested for drugging her friend's family - in fact what happened to Derek's family, did they just wake up in the barn and go home without notifying the authorities that they had been drugged and kidnapped?
Those things are loose ends - however, it doesn't detract at all from the enjoyment and sheer amazingness of the whole story, which was totally epic.
And as to people saying Kali wouldn't have been able to help El escape because she would have died in the explosion - actually I think there was a gap, between when the soldiers discovered everyone in the lorry and when they realised El was standing inside the gateway to the upside down - maybe about a minute, actually I think slightly longer before the explosion began, so there would have been time for her to befuddle everybody with a vision of El while the real El slipped away. So Mike's theory could be right - although I don't know if she would have left her friends in that situation to save herself. But, knowing that she would be used by the military and the cycle start again maybe she would have felt that stopping that scenario was more important. Anyhoo, that'a my theory about that.
Amazing. Stranger Things will be remembered as THE tv programme of the decade. Hats off to the writers - I hope they come up with something equally as amazing in the future.