I will first state I am a big Park Eun Bin fan so there is some bias to the review. She was awesome in King's Affection and Attorney Woo. She gives off Audrey Hepburn vibes and I am sure she will star in many more addictive KDramas in the future.

I will start off with the good parts:

-Park Eun Bin is in this! I don't need to say more.
-The story telling of the tragic back story of the FL and ML's childhood and abusive past is told well and you get a sense that they are holding onto each other as two lonely teenagers in a scary traumatic world.
-Who is the adult Jung Ki Ho? The story tellers keep you guessing. Who should the viewer root for as the love interest? I will take my stand, I am rooting for Kang Bo Geol.

There is room for improvement (there is no bad in Park Eun Bin's dramas haha):

-Her character and behavior is a bit too ditzy, perhaps she didn't get to emotionally develop since she was isolated for 15 years so there's some emotional stunting.
-The aspects of her surviving on the island is unrealistic and how she is still so pale when she is outdoors in the island. Where is the tan or sunburn???
-The two male leads being too helpful too soon to her when they barely know her
-Her relationship and idolization of a faded popular singer who fell from grace.