I'm going to come and say the quite part out loud. Spoilers ahead.
I'd guess 45% of the negative reviews of this show are xenophobic garbage wrapped in thinly veiled racist logic that Netflix should be producing American shows and American shows only. I haven't read all of the them, but enough to get the gist.
We get it, you're tired of not understanding why people like Korean art and culture, but you don't need to be a digital Karen about it.
Another 45% of the negative reviews come from people that appear to be attaching their own values and dogma surrounding sin to the premise of the show. They then proceed to get bent out of shape over the fact that the sins of the victims in the show don't rise to "be murdered and dragged to hell" levels.
The premise of 'sin' in the show is not written in stone... that's sort of the whole point. Sin is a tool used by religious leaders to guide -- or in most cases manipulate -- the masses. That is put to spectacular and hyperbolic use by the writers to craft what I think is actually a pretty smart commentary on the power and place of religious institutions in South Korea (and the world at large).
The final 10% of the negative reviews are presented as perfectly valid "it just didn't tickle my pickle" opinions with some genuinely good critiques of the show's script, pacing, special effects, etc. etc.
So why did I just defend the show for like 3 whole paragraphs only to rate it 3/5 stars? (hard spoilers below)
TL;DR:
The time and cast shift between episodes 3 and 4 is clunky and leaves a lot to be desired for the overall cadence of the show. To be honest, I would have been thrilled to be given about twice as many episodes to properly flush out the death spiral of Seoul under the New Truth into a 1984 meets Clockwork Orange kind of dystopia.
I sincerely hope we get a second season to explore the coming culture war the show sets up in the final episode, and that the creators apply a little more traditional cadence to keep the audience from being jarred between the first and second halves of the season.
The Long Version:
+ The show is a well acted drama with a supernatural twist and gives the viewer a lot of social touchpoints and commentary to chew on:
*The arrival of a man who claims to understand the wills of god for his children, giving us a handy-dandy fatalist do and do no list of sins. Who chose this moral code, god, or this man? Fun stuff.
*What role does and should religion play in our society if it's a) easily manipulated b) dangerously good at pushing people to extremism c) can literally all be predicated on a lie?
*What are the differences, really, between a cult and a religion?
+Great acting by much of the cast. Do not watch the dub, just don't. It's always bad and you lose a vast amount of the body language and facial expression timing.
+A genuinely exciting twist at the end which sets up several new avenues for the story to take.
+Not afraid to kill characters. This is good, as it keeps it feeling emotionally grounded when you know you could lose that person you really like.
-The pacing is arduous. Not just in the time jump halfway through, but within many of the episodes as well.
-Repetitive action. The murders are a little video-game finishing sequence feeling. It's a bit of "what's goriest way we can bludgeon this person to death" answered with "lets have them stab him this time."