I binge watched this so bad, I started yesterday evening and ended in the same night! I didn't think I would watched all at once, but I have to say that it was really good. It comes with a lot of revenge dramas around, revenge is a tipycal guide line in kdramas, but sometimes it gets tired to watch or you just start loosing interest because it's dragged, this one is really well made in my opinion, the pace is stable and the characters are well developed.
I mean, with the end of season one it's not like nothing happened, but the real revenge it still has to come, within all season one the story is built, you see the developoment of all the characters and some new entry, and how the protagonist is paventing the way for revenge, and did not get bored, you stay there and watch every episode with curiosity.
The acting is amazing, a really high level, you can receive all emotion from them, the choices for young/adult are really amazing as if they 're real! And maybe I' m a sucker for villains, but I have to say that Shin Ye Eun and Im Ji Yeon who play the same character (young/adult) are really spectacular, when I looked at them I got shivers!