I now understand why this is one of the best dramas in Korean world. It was perfect for me a I cannot say anything bad.
Story: The story was interesting for me, the mystical atmosphere brought this lovestory to a new level. Sometimes it was a little bit melodramatic - like a typical korean drama but overall I find it full of suprises that kept me watching and wanting more. Storylines were always finished and explained - for me it wasn not like they just threw something new unexpected. Each one of the characters had his own mission and drama did not forget that. (Spoiler) Kim Shin was so lonely and life did not matter to him but he found his reason to live. Grim Reaper wants to find out about his past life and he finds Sunny. Eun Tak had life full of trouble and sadness but then she finally find her home. She then sacrifices her own life but finds her way to Goblin. Sunny is just normal human being when she finds herself around abnormal beings. In the first half of episodes they are building the relationships so everything goes slower.
Cast: They are great. I do not mind the age gap between Gong Yoo and Kim Go Eun because their chemistry is chef kiss. Bromace between Gong Yoo nad Lee Dong Woo is cute and funny. Yoo In Na is charming and all of them are building the atmosphere.
OST: I love all songs. Even if you do not want to watch this drama, please, just listen to soundtrack, you will love it. Unpopular opinion - I love Round And Round even if Heize sings it.
What can I say in the end... The ending is bittersweet while Goblin will always see Eun Tak die and he will stay alone.