I’m fond of South Korean television shows, but "Agent Kim Reactivated" proved to be an exhausting experience. The main problem, as I see it, lies with the writing. It's marketed as an action thriller, and yet there seems to be hesitation in moving forward with the narrative. Instead, what we get are constant, bothersome diversions—changes in direction and emphasis—along with a large number of unnecessary supporting characters. These issues are compounded by a character who is unbelievably meek, exaggeratedly humble to the point of seeming ridiculous, and supposedly also a covert operative/deadly killer. The performances are acceptable, but that’s really the only positive thing about this series, and not much of a consolation given everything else that goes wrong. Ultimately, a script lacking direction and implausible character portrayals spoil what had the potential to be something worthwhile.

Source on TMDB