First off, I do find this drama a bit overhyped. The first two episodes were good hook when Hwang Shi Mok stumbled across a dead body in the house, and he went on to investigate that murder case. But I found the sequential episodes that follow from episode 2 a bit flat and boring, and the show only started to pick up its pace again at the end of episode 7 upwards. The show was written cleverly in a way that makes literally everyone around Hwang Shi Mok suspectable, and that's admirably its biggest strength. However, I would argue that despite the writer's best efforts to mask the identity of the real mastermind of the murder, from the start it was quite obvious who seemed to have been the most corrupted among them all, so I do find the conclusion of the story wasn't that thrilling and suspenseful. The anti-climax, however, is the mastermind's motive at the end explained in full which was a great twist. Therefore my favourable rating for its story is more of an appreciation for its complexity, rather than a lasting impression it could have left me.

There are two main characters listed on the show, but I do find that only Hwang Shi Mok has enough enigma to keep me genuinely invested in the show. Even when I say so, I do find that the main lead very capable, but not charismatic enough. Psychologically speaking, charisma is perhaps a trait that is a privilege for people who are able to masterfully control their emotion, and Hwang Shi Mok is hardly a person able to exercise that. Thus, as much as he is a very rational character who only thinks logically and pursues justice objectively and therefore would come across charming to other people, it becomes the very reason I find it difficult to connect to his character. There's a comparable emotionally muted character in kdramaland portrayed by Jang Hyuk in A Beautiful Mind, which was given enough emotional background and development for viewers to sympathize with him (even though the show was cut short by two episodes due to fierce rating competition during airing time). In that sense, I do respect whenever a writer decided to create a male lead character that has a medical condition of suppressed emotions. However, there should also be enough background materials to properly explain the male lead's behaviour and motives from past to present, which I found this drama has not done very successfully.

Han Yeo Jin as the female cop was quite uninteresting to me. Yes, she's a competent police officer who pursues justice relentlessly and there's a powerful scene where she confronted Hwang Shi Mok about corruption in the police force, but just like Hwang Shi Mok, she wasn't given enough depth beyond her role as a police officer (in fact, hardly any if at all). Young Eun Soo was definitely the most irritable character in the drama to me. Although I admit she comes across very tenacious about her mission, oftentimes she was so reckless and single-minded that it was unbearably difficult for me to like or understand her. I really wished her character to be a lot more sophisticated and cunning, but graceful. Seo Dong Jae is the character whom you literally want to punch on the face because he's so good at being shady/bad, which adds the interesting colours that the show is lacking from its main leads. The only character that was given the most depth and inner motive in this drama is definitely Lee Chang Joon, and the actor delivered it flawlessly.

There's not really a memorable BGM anywhere and I also find this drama not very re-watchable.

If you are looking for really clever screenwriting that tops this, I'd recommend Hello Monster, WATCHER, Confession (2019) and The Crowned Clown instead.