Viewers intending to watch this show should be aware that it is extremely violent, gory and depicts shocking levels of physical violence.

It is a mystery to me how such graphic violence can be rated as suitable for viewers from the age of 15 in S Korea!

Oddly enough, harmful objects such as the blade of a knife are blurred so us viewers aren't exposed to the shocking sight of a bare blade (?!) -- but seeing a killer smashing in the heads of their victims, people mindlessly kicking and bashing people (usually WOMEN) to a bloody pulp while they are lying on the floor begging for their lives (and they are NEVER ever trying to defend themselves, kick and scream and shout and cry or hit back) is shown at length and in detail...

I am really starting to hate this violence trope in Kdramas - specifically in crime/police thrillers...

I watched this show for Jang Hyuk and the acting was good (no surprise there!) but I was disgusted by the gore and violence. I liked the more humane side stories, when the police discover the scandalous exploitation of the poor, homeless, mentally-ill and help those victims.
Those storylines were very well-portrayed and I would have liked it if they had focused more on psychological insights to the characters (i.e. Moo Jin Hyuk's marriage before his wife was killed, his grief process, the father-son-relationship, Kang Kwon Joo's pursuit of her father's killer, her struggles/grief and determination to right past wrongs...) - but I guess this is just not that kind of show.