Skimming through the comments since I last added one here, something seems to have become pretty apparent: if you enjoy stories that challenge you as a viewer and take you to some dark and uncomfortable places, chances are likely you will love this drama and think it incredibly well-written. But, if you're really only in it for romance and like to have a more passive, feel-good viewing experience, there's an excellent chance you will hate it (especially the last four episodes), and think it was stupid and the story unraveled at the end. This isn't a story about romance - at its core, this is a story about love and how it (or lack of it) shapes people and affects the decisions they make. I won't go too far into spoiler territory, but all of the characters in this show - from villain to supporting cast to the leads themselves - act in service to a very deep examination of love in its varying forms. It's made pretty clear the villain became the person he was because he was unloved and abused as a child - nurture over nature in this case - and in his most sensitive moment, sitting in the church in the final episode, we see that quite clearly. All of the main and supporting cast, when faced with a decision, made those decisions based on what they were willing to sacrifice for love, and, in those moments, we find out who they truly are. Aside from the shooting at the police station (which, arguably, was only there to show how truly evil things had gotten), there were no "meaningless deaths" - every death served to progress the story and show us who these characters were when push came to shove. I agree with one of the featured reviews above - the end actually left me with a sense of hope, but I can't really distill all the parts of what I saw and felt into a single, easy reason for why I was left with that sense of hope... which I think is pretty cool. Anyway, this is a drama that will stay with me for a while, and I'm very happy for that. It's challenging and painful to watch at times, but, when all is said and done, one of the most emotionally satisfying dramas I've seen because of those very qualities.
(Brief footnote: I know people have said the scene between HDD and KPS in the church during the final episode was out of character for HDD, but I pretty much took it as given that the souls he consumed tempered him somewhat along the way, and saw that happening throughout the course of the story - both in appearance and temperament, the HDD we started off with changes as the story progresses, so, not only did that scene not feel out of character to me, but I really enjoyed it. And, the acting by both of them in it was fantastic.)
Well, contrary to pretty much every other review, I thought the ending was beautiful and perfect for the story, but it was pretty obvious to me it wasn't going to end well for anyone about halfway through the series, so I was expecting it. Also, it's one of the rare dramas I've seen over the years where I thought the writing got stronger and more nicely focused as the story went on. It was a heart-wrenching watch, for sure, but I thought it was incredibly well executed on every level from start to finish. A rare 10/10 viewing experience for me.
(Brief footnote: I know people have said the scene between HDD and KPS in the church during the final episode was out of character for HDD, but I pretty much took it as given that the souls he consumed tempered him somewhat along the way, and saw that happening throughout the course of the story - both in appearance and temperament, the HDD we started off with changes as the story progresses, so, not only did that scene not feel out of character to me, but I really enjoyed it. And, the acting by both of them in it was fantastic.)