UGH, this drama, I finished it in like 3 days and I kind of have a love-and-hate-relationship with it.
Its start very promising and the story is a bit creepy and gloomy, but very interesting. The second episode is where you think "Ok, WTF is going on?!"

I think it's a very good drama with a lot of twists and storylines only a psychopath could think of. It really messes with your head and sometimes I even lost track, because it was getting kind of like a labyrinth.
I liked the love story in the drama, it was sweet and a contrast to all the gloomy stuff.

Personally I didn't like the ending, so I probably wouldn't watch it again, that's why I gave only 5.0/10. I mean it's an ending I could be ok with but your heart hurts while it happens and you're left with being a little mess.

So, you can see that this drama really got me hooked and made me sad and cry.
This drama gets you really and you start thinking about many things, but as it made me so sad...ugh I dunno, it's good. watch it.