The drama had a good mix of cases and personal attachments which helped raising the tension and to have higher stakes. Most of the cases were interesting and entertaining. On the other hand, season 2 cases had less personal attachments other than 2 incidents, one around the middle and another for the last case. Stella existence was problematic to the drama, both the character and the actress. She was out of place and her scenes were insufferable since her introduction. She was added to the drama as a fun and quirky element but that backfired immediately. Sally was her replacement in season 2, the drama attempted to replicate Stella but ended creating a worse version which made her scenes even more insufferable. I can't stress enough how insufferable both of these characters were. Season 2 had another unsuccessful addition, that is the character Do Ji Han, his character took away from the drama rather than adding or enhancing any value. Judging by what they did with season 2, It's preferable to not get another sequel. Unfortunately, they left a lot of threads open for a possible continuation. On an unrelated note, the corpses in season 2 had more censoring than season 1.
