I'm not usually a fan of suspenseful sci-fi dramas like these, but I loved this! The show did a good job of creating three-dimensional characters with both flaws and redeeming qualities. I have so much respect for an actor who can play two completely different characters in the same show; Seo Kang-joon did a phenomenal job. I was similarly impressed with the character Ji Young Hoon, played by Lee Joon Hyuk. I usually hate the loyal henchman character, but he kept it fascinating.

While I wouldn't listen to the soundtrack outside of watching the show, this is one of the few K-dramas I have watched where I felt the music was spot on for each dramatic moment. Everything was carefully orchestrated for each mood. The plot was always thrilling, with actual twists and turns that I did not expect. I would say that the justifications for some of those plot twists were a bit shaky, but I was kept from losing interest by the way that the plot actually helped to develop the characters, their motivations, and their backstories. I generally hate suspenseful dramas because they usually have twists that do not reveal anything about the characters, but this was a refreshing change.

At the most basic level, I would say that this drama's strength is really its characters and its acting. I have never seen a K drama make me sympathize with so many "villains" and doubt so many "heroes."