The story idea itself is really good in my opinion, but I was disappointed by the ending...quite a lot...
I loved the supporting cast, especially the trio of grim reapers and Han Moo Gang's police team.
The character Kang Ha Ram was a bit fustrating for me.
To the ending I have to say that it seems a bit unlogical and weird for me. Weird in the sense that it doesn't fit to the story after Grim Reaper is receiving the highest penalty that he could possible receive. For me this "sudden happy ending" doesn't fit to the story and that's why I was disappointed...
The OST is good, though.