I have seen numerous Korean romance dramas with the interesting supernatural flavor.As fat as this drama is concerned i would say DONT WATCH IT!
Why? you will ask.While the plot around the drama is an interesting one i.e. the dead protagonist magically travels ahead in time before his death etc etc. the overall execution of the plot in the various episodes (from the very first is very poor). By this i am referring to:
1) the flow of / transition to new scenes in each episode is very abrupt.For instance the entrance of characters (actors) from one scent to another is not smooth.You'll notice this if you see a couple of episodes and understand this point if you have seen other well made Kdrama.
2) the acting is not up to the mark.The emotions , expressions and mannerisms of the female protagonist (older version) are either very dull or out of place which was a letdown and the male lead i felt was overacting in many instances / under acting for a given situation in the drama.
3) And the main emotion of all - "SURPRISE" was laking in all the actors !! I mean your friend who had died 12 yers ago came back magically and most of the characters (e.g. the female lead , the male lead's brother etc) were not surprised? they just took as a matter of fact that he is back with a very weak emotion of surprise? especially the female lead. i mean come on! The main context of the drama was portrayed weakly.