Bad Guys has it all. There is a great main story line which includes mysterious serial killers, betrayal, and deep feelings of injustice as well as understanding, redemption, and forgiveness. Each character's story is also interesting and there is excellent character development with out the character's basic personality changing. The chemistry, the dialogue, the action, and directing come together perfectly. I enjoyed every episode and hope that there will be another season. I love me some Kim Sang Joong. I have seen many of his dramas and enjoy his characters, but I have to say that Oh Goo Tak is my favorite. He perfectly combined strength and vulnerability. Park Hae Jin portrays Lee Jung Moon as a psychopath of which a person can't help but feel sympathy. Jo Dong Hyeok is beautiful as Jung Tae Soo. I love his character the most. Ma Dong Seok is so enjoyable to watch a Park Woong Cheol. I felt him. They are all attractive in their own way. The other actors are good too. The music is appropriate. I will probably rewatch this just before season 2 starts (wishful thinking). I admit that if you are not into action/mystery dramas that you might not like this drama. However. It is so much more than just that. I recommend this drama to everyone.