The series is unique to me because the main lead isn't even the center of the story. Most of the time, we were in the point of view of Jang Nan Gam (Son Suk Ku). At the beginning of the episode, we were in the perspective of Lee Tang (Choi Woo Shik). After being chased by the police, we were mostly in the police's point of view. After that, it became more mysterious with the introduction of Song Chon (Lee Hee Joon), who drove the series until the end. For me, that was a unique way of writing the story, and I love it.
The plot is very fresh and interesting. I can't recall when a series or movie had such a refreshing plot, especially in Korean drama or movies where characters can sometimes feel repetitive. The switching of the point of view is truly lovely and unnoticeable. Lee Chang Hee (Director) also directed "Strangers From Hell," and it's no wonder this series turned out to be good. He really did a good job. Additionally, the first few minutes of this series have to be the best-directed sequence of all time.
The transition, THE TRANSITION. It is insanely addictive to watch how they transition from 1 scene in the past to the current scene, or from hallucination scene to reality. And how they project the future character into the past. And they did it multiple time flawlessly.
Furthermore, one aspect that many didn't talk about is the use of background music, which was really good. On top of that, the gorgeous cinematography adds to the overall experience. Let's not forget about the acting; every actor performed a marvelous job, especially Song Chon, who, in my opinion, shone the brightest in this series.
Some say that the pace became stale in the middle of the series because of the addition of two new questionable characters in Busan who were having a crisis, which I understand why it became boring. However, it picked up its pace again after that. Nonetheless, I definitely recommend it.