This series has a good premise, good writing, and I think really great acting. But then it died out at the end so completely, so abruptly, that I wished I had been warned about it advance.
I am legitimately curious about what the story was with this. I don't know if this could possibly have really happened, but it really seemed as if it was planned to have a much longer season, or even a second season, and then those plans were scrapped around the time they were shooting episode 16, the show being cancelled without warning, so they had to wind the whole thing up unceremoniously, turning episode 16 into the series finale without being able to answer unanswered questions or give the characters satisfying conclusions to their story arcs.
Again, I don't have any information that this was really the case. But it would explain what I saw.
Honestly I think it would be a waste of time for me to discuss some of the genuinely interesting plot elements in episodes 1-15, because in each case the account would end: "and then the series ends and you don't know why this happened, you don't know what happens next, you don't know what happens to the Korean legal system, you don't know who is going to get together with who, and you can imagine a way that it would work out okay for the innocent people and the bad people would get what they deserve, but it would have taken a few more episodes to work that all out and those episodes were never aired."
That's really all I've got to say. If you think this is an extreme hater view, for some reason, you can put in 16 hours watching this and see if I'm wrong.