I really liked this drama, definitely an 8.5/10 in my opinion.
I loved how they used this gorgeous cinematography and lovely music/ost that I more often associate with melodramas rather than crime, it worked wonders! Or is this maybe a melodrama disguised as a police procedural?
I also appreciated that they didn’t use corruption or something like that to explain what happened in the past or to hinder the police in the present unlike the majority of k-dramas. It would have been cheap.

Basically, the only issue I have is with the antagonist, I found his mostly annoying demeanor and smugness very frustrating. It was exacerbated by how much I loved the vibe I got from the kid playing him in the flashbacks: he showed both resilience and fragility, doubts about his real self but also the determination to prove everyone wrong. Anyway, the character study behind everyone was spot on despite my quibbles.