drama is indeed good, though nothing special. the best part is the friends are real friends till the very end and this is one of the biggest YES for me in Dramas.
the creep game is on level God, though it was weird still was funny.
In overall chemistry is good, story is ok- there are real psychos and detestable human beings.
In overall I would give 7.9/10 - if you have watched many alike dramas and is looking for something similar style, then this is pretty fine. If it is first time- I'd rather advise to look for better dramas. Not bad, but not good enough to put in my top 10.