There is a lot of famous actors & actresses from both Japan and Korea in this drama.  Music was great and Yutaka Takenouchi still looks stunningly good.  This story is like a complete copy cat of the famous HK cop movies: Infernal Affairs.  Acting from both leads is amazing. 
While watching that drama & if you know some programming, you will probably find it hilarious too see how coding a few for loop can create program that will destroy Japanese economy.