Inspector Koo, or A Wonderful Sight is cleverly written and fairly stylish. The performances are all good-to-excellent, especially the leads. The best Korean comedy/drama? Perhaps not, but I have never seen a show have its imdb rating score swoop about so much!
At this time of writing, 88 out of 117 viewers rating it gave it a score of 7 or higher, with the largest group by far giving it a "10". Yet it now stands at 6.6, which might put future audiences from giving the show a try. Give it a try, anyway, I say.
There are claims it is trying to be a Korean version of Killing Eve. In a way, it's closer in feel to Sherlock. Not at that level of quality, but in the sense of it using graphics and structure to tell a story about a deeply flawed detective using almost superhuman skills to track a killer of near-supervillainous talent.
Inspector Koo is a fun play on manga comic books, and has some great comic moments. I would actually rate it a 7ish but felt there should be something countering its low score.
