First, let's talk about the extraordinary cinematography/camera work. 
My best appreciation of cinematography and soundtrack. The people who worked for those 2 sections really gave fantastic output. Coloring, lighting too. To precisely say the Cinematography's a truly magical feast here that elevates the dramas story telling to different levels. The slow motion angle shots/slow moving forward frame/slow backward moving frames are really, really well done. It's like cinematography/camera work magic. And writing is good, except for the last episode, Lee Su Hyun's death.
 
Acting is extraordinary, especially. Chae Won bin really, really done a pure masterclass. I know her character role is i
emotionless person throughout drama, but for an upcoming emerging actress it's not that easy to perfectly convey the same expressions from the start to the end of the drama and to keep watchers engaged. Also every actor gives their best performance.


But the disappointing thing is—no strong story in the detective subplot, same weak writing on police and detective procedural. The Writing in this core area feels underdeveloped or formulaic, with not thrilling investigative elements used as to push the story forward. They do nothing except suspect and arrest the main leads. Writers are using this police procedural plot just for the story engagement and to move the episode forward. Except for this weak writing, every aspect is good.