This drama reminded me of the "Liar game" manga - same game for survival style and the MC tries to save everyone, even though it doesn't always go that way. Episode 3 was quite touching and overall there were some twists along the story that kept it entertaining and gave the sensation - I have to know how this will end.
I loved everything about this drama, except the wigs - I really do hope that next season they'll find a better hairstylist. I have also wondered how much did they pay to have the streets of Tokyo and the subway emptied in broad daylight.