Excellent. Consistent in its plot, straight to the point with just enough episodes to say the story without diverting to irrelevant sub plots, strong character development, great acting from all the cast, with a female lead that understood her role and made it her own, suspenseful action scenes, very nice OST with some low bap bits that I personally favor and a finale that for once made sense. I wish more dramas were that good.

10 out of 10 from me.

P.S No need for a second season. This drama is complete as it is and there is no need to expand or try to repeat it.