I started and finished this in one day, and, to me, it was a frustrating ride. I was patient initially, but I began losing it near the last six episodes.

The drama is certainly engrossing... to a point. Gosh, where do I begin?

The writers successfully built the suspense, mostly by beating around the bush just so to stretch out the length of the drama. Some characters came - like the cute, awkward ex of the FL - and vanished; very frustrating and unnecessary. The cinematography was good, adding to the dark theme the writers intended, but it made me feel detached to the story. Furthermore, the painstakingly slow pace of the conversations with extended silences in between made me skip a few seconds. Perhaps my watching it in a day led me to be so impatient, so take my opinion on the pace with a grain of salt if you don't plan to binge-watch.

The music was good. It was hardly out-of-place and complemented the character of the drama. However, they could have added music to a few moments to add life to the story. Good music always enhances - this feature was slightly underused.

For acting, I will start with the positives: Park Sung-Woong and Seo In Guk did great as main leads (the side actors were good too). In Guk embodied Kim Moo-Young's character well enough for me to be creeped out by him. Personally, however, Sung-Woong stood out the most - he portrayed the various colors of Jin Gook amazingly. After his moment of insanity with Moo-Young, Jin Gook's internal numbness felt real; I felt for him despite my disappointment. Jung So-Min did not really convince me as Jin Kang, or perhaps she did (if the character was meant to be what I got from it). Her expressions were usually blank; for example, when Moo-Young mentioned her "gentle eyes" or "look of pity", I genuinely could not see it on her face. She usually gazed with curiosity or disbelief (the latter annoyed me greatly), and that's it. I feel like an exception since I'm unable to see how great of an actress she apparently was here.

The characters? Goodness, their antics made me want to rip my hair out, especially our FL. She pretended to be so morally upright, turning out to be the opposite in many ways. I wanted to grab her by the shoulders and shake her. She could accept situations easily and move on, which is certainly commendable, but, gosh, don't start sleeping with your late friend's boyfriend who was a total asshole to her. How she could be so disloyal to her friend is beyond me. While knowing that the ML was deceiving her, she kept quiet and let out an "Oh" as a warning, which clearly didn't do the job. Forever talked about ending aquaintancehship with the ML but never lived up to her words. It offended me how easily she forgot that her new boyfriend actually led her bestie to her death. The FL mentioned her older brother in a fond light, felt she owed much to him, but her actions were so selfish, it hurts. I was unable to empathize with her struggle with guilt over being a burden. I understood, but it never convinced me to root for the character. I won't even comment on the ML, since he was obviously not stable, but the poor writing apparently wanted him to be regarded as a misunderstood being. The brother seemed reasonable enough, not being swept by people's words, but certain actions of his in the end sometimes disappointed me. In my opinion, the writers tried too hard to paint the characters in grey, and it backfired. In my opinion, grey does not mean justifying wrong by narrating sob stories - grey means to see the reasoning behind actions and thought process, and letting the viewers empathize.

I genuinely wanted the toxic relationship between the ML and FL to be shown in an un-romantic light, but it seemed the writers wanted us to cry over the tragic end to their brief period of infatuation. I'll admit, some scenes were touching at times, but should that change the nature of the relationship?

The interactions I enjoyed were the brief moments of sibling bonding and healthy friendship - Jin Gook and Jin Kang had great banter; and Jin Gook and Tak / Cho Rong. The ML's false memory of his father being a policeman searching for him was bittersweet when it was revealed who he was actually thinking about.

The plot ties together well in the end. We get to see many things, after much wait, and some questions aren't answered, like the ML's motives with the first murder case (or maybe I missed it in my skipping spree near the end). The potential to greatness was there. The idea of "love conquers all" led to its downfall. They should have shown how, realistically speaking, such ideas play out in toxic relationships and sociopaths. If the writers intended to tell us that what was unfolding between the leads was poisonous, they did a poor job. What I saw a weak attempt at redeeming the ML and FL (her decisions, to be precise).

I just feel sad for the brother: he did not deserve this.