First of all, the thriller genre tag is a total bait. This was just a mystery. Aside from that, the show could be huge. The idea's unique and strong and the acting and directing was great. I picked it up because of its douban rating and the combination of mystery/thriller which I love.
Yet I kept thinking why this (which instantly gave me pleasant vibes of "Signal" + "For N") was taking me so long to finish. In the end I realized I kept losing focus or feeling bored during the past story line, which was unfortunately 2/3 of the entire story.
I found the plot realistic in all the wrong parts and pretty unrealistic in the others. I mean, a person highly educated in law, buying an autopsy report with money publicly from the source himself? That's just so unrealistic and dumb. What's the use of illegally obtained evidence anyway?
The corrupt side are willing to kill so many people in flashy ways just to dump some evidence? Why make such a big scene? Just put all the blame on someone and get rid of the evidence cleanly.

Then when it comes to characters, suddenly they're so realistically average brained, it's boringly predictable. They take suspects to the same station lead by someone they know is involved. Twice. They clumsil clumsily loose evidence. Get easily provoked.

Another problem was captain Ren. She started explosive and for the first time I found a female team leader charming. Then she was almost completely sidelined and had no influence on the story. Not sure what the point of her was. Just to have a female in the police team? Either her or Yan Liang. They should've chosen only one.

The wallet scene was a masterpiece, though. I just know it's gonna stay with me from this drama.