I decided to watch this because of lee dong wook and because of the story line. I mean a person who changes every single day? Never heard of this kind of story. I watched it and oh my god I loveeeeeeeeeeeeeeeeeeee this movie! Hyo Joo's acting is just spectacular. I expected this movie would be a fun one like I was eager to know how this guy actually cope with his condition? It's like a roller coaster of feelings when watching this. Similar to the character, your feelings when watching this changes too (idk maybe it's just me). It's 2 hours long but it doesn't feel boring or dragging. It paces just perfectly. Overall is just great!