Well, I mainly watched this drama for Lee joon, I didn't even look at the other cast or what his role actually was, but the cast was good as I begun watching the drama. I thought that the plot is pretty interesting and unusual and that what motivated me to watch the drama. For the acting, I really liked the acting, except few scenes that it was confusing to understand the character reaction. I really liked Lee joon's acting.. it looked so real, that I had to look in the beginning at old photos and videos to see if he naturally smirks instead of smiling XD.. The story was very interesting, however, I felt bored in few episodes in the middle.. It was really confusing to keep up with what was going and I always doubted what was going on, but the last episodes were fine. The most part I loved was the OST, it suits the drama very well I never liked a drama ost as much as I loved this one.