Glad to be a part of the ‘club’ then, hahaha. I’ll probably rewatch it too when I have extra time, or next year, or next week, or whenever. I’ve honestly thought about the main question posed in the drama quite a lot, since I watch Criminal Minds regularly. I really didn’t understand why the Doctor said ‘I won’ before he fell. I mean, what game did he win? Did he manage to make them monsters, is that what he meant? Because as far as I know, it wasn’t a game, he just asked the question.. -S

Fun fact: the original title of the show was going to be Monster. As in, “are monsters born or made?”

As Moo Yul said at the beginning of the show (and each episode), this was the story of how he became a monster in order to defeat a monster. That’s the “game” (really, psychological experiment) the doctor won, or believed he won. Yoon Su might have opted out of the experiment by choosing a different path, but the other students had to tap into their inner monster and destroy someone outside of of the law in order to better their lives. 

I believe that’s the generally accepted viewpoint, although as I said, it’s ambiguous enough that you can start up a whole new debate about who was the “true” monster or if the doctor really won or if it was just hubris or what. Which, I guess, is another way the doctor kinda won, since that’s the conversation he wanted to have in the first place.