Story:
Kim Do Hyung: "joo young please wait a little more." "i will find joo young."
Detective Cha: "i'm sorry kim do hyung, we lost (x person)", "i'm sorry kim do hyung, (x person) is dead."
Yoon Joo Young: " i don't have right to do that.", "i'm sorry do hyung, it's all because of me."
Seo Jin Ki: "yah, banker ajusshi."
Chairman Kang: "will you (do that)?"
Detective Park: "stop talking cr*p."
Although the show was full of promises and potential in the beginning, i regret to say that the whole story can be summarized in the lines above.
A not so regular bank employee with special military skills going after the unlaw organizations to find his lost fiancee was a rare plot line by 2015 (although people going after baddies for a loved one is nowadays almost overused) so i remember being really interested in the project when it was first announced. plus it is written by Cruel City's capable writer. But unlike that one, the supporting roles were criminally underused and poorly written, i think this is the main problem of this series. the whole story revolves around one person (or maybe two - with Seo Jin Ki) and everyone else is just a side character to appear once in a while to create new challenges for Kim Do Hyung. Although Cha Yoo Mi is listed as a lead,  i beg to differ. She was such a frustrating character, she had no depth, never ever did something worthy on her own, always put herself in danger and always lost important witnesses or suspects. I could let it pass if she was a rookie detective but she is suppose to be a chief detective. I could say the same thing for almost everyone else minus Kim Do Hyung. Yoon Joo Young was such a mystery to me. She started badass, going after the mob boss she was working under and daring to co-operate with a detective. Then turned into a complete damsel in distress, then surprised me so much in her car scene in episode 5 and turned back in damsel in distress mode once again to suddenly go (pretend) badass in the last episodes. She is a major character for sure, but i think the 'show' did not love Yoon Joo Young, herself, but the idea of her.
I'm not saying the drama was bad, it is still superior to (most) dramas of the same genre, but it is a pity how much more it could have been. You had so much time to focus on the relationships between Kim Do Hyung/Cha Yoo Mi, Cha Yoo Mi/Yoon Joo Young, Seo Jin Ki/Hak Soo, Seo Jin Ki/Son Hye Joung , literally every one and anyone else. Just half of the writing in the Cruel City would do, but instead you just put Joo Young in danger repeatedly to rescue her repeatedly for 16 episodes.
Acting:
Kim Mu Yeol hard carried the show. His performance was followed by Ryu Seong Soo who was just as awesome. Both Lee Shi Young and Lee El are my favs but they were so underused that i'm hugely disappointed. I won't count every one, one by one but in short the whole cast was perfect in acting aspect. It was just that the characters were superficially written.
Music:
Love the soundtrack. The series is a part of my "on the treadmill" dramas, and the soundtrack plays a big role in this alongside the action scenes.
Rewatch Value:
I enjoyed the series over all and would rewatch it, maybe in 5 years once i forget the details.
Overall:
Again, the series was an enjoyable ride. But it is a huge '-could have been'.