I had this on hold for over 3 months.I decided to continue and finish it and it was a really nice choice.
So my thoughts about it.

Music: Good but not that good to stay inside my head.

Cast/acting :Except Yoo Jae Myung(the detective) and Yoon Gyung Ho(the psycho prison guard) i haven't watched the rest of the cast in any other drama.But i think the director or whoever chose them for their roles made the right choice.
The acting as expected was flawless,real and natural.Everything was smooth and in the right dose.

Characters:Usually in dramas i pick my favorite character and after finish it i think about him/her over and over again.What made me choose him,which criteria etc etc.But in this one i have no favorite character.Or to put it right i wasn't excited at any char in particular.Noone stood out to make me say "wow,this is a really interesing character" Iam not saying chars were bad written.But they lack that little something to make them really exciting and memorable.The spark to ignite the absolute fav char wasn't there. I will explain it better when i talk about the plot.

Story/plot :Touches the perfect 10.So very close.9,5 is not bad after all!
So the story is based on-what else!-Corruption!Always here as in most Kdramas.But in this one although is the unifying element,lays in the background supporting the main story and gives depth and essence to it.
So this series is all about a story to be told.All characters combined to tell us the story.They just serve the storyline itself.Their chemistry was there all the time.What i liked the most was the dynamic of the team.Everyone's fate was connected to each other's.Characters connection and involvement is given in a very clever way keeping our interest high.So many tangled threads.So many random dots waiting to be connected episode after episode.The story is interesting,painful and thrilling.Every episode give us a little something,keep feeding our heads with crumbs just enough to keep us busy thinking ,until the next one.
This is called "a job done right" to me.
The writer really loved to torture our main lead by giving him so much pain he had to go through!The pace is really nice.I wasn't bored at all and this is always a plus to me.Of course the drama has few flaws too.Sometimes too obvious and some others a bit annoying..Like the ML touches everything in a crime scene without gloves!Or forgets his phone at the most crucial and important moments!Lol.But this is just minor!
As a whole the story is captivating and you easily pass those little mistakes because the drama is really enjoyable.
I loved how the puzzle pieces fell on the table slowly forming the bigger picture.They didn't rush revealing clues,they gave us the time to do our own thinking about the plot.I really appreciated this.
If i could combine Stranger and this one(i mention stranger cause is in the same category with similar plot)it would be a perfect 10!What i didn't like there,liked here and Vice Versa.Obviously i recommend both dramas if you are into the genre.
And finally i give the rewatch value a 5 because usually i do not watch dramas for a second time unless is light and fluffy(like BLs for example)
P.s i dont spoil things in my reviews or at least i try not to.So if you like corruprion.crime investigation.law themes etc this drama is a really nice choice for you too.
Good night all!