I loved it. I really liked the chemistry between both actors and the entire cast did a great job. I was abit hesitant with the first two eps but since it has such a great opening sequence, i continued and things only got better and better each coming episode. The only thing that didn't let me give it a 10/10 was that it needed a couple more episodes to have proper closure for all the characters but it was overall one of the best kdramas this year and great action, thriller and romance combo. I'm def going to rewatch it as well

SPOILER
Some things were left unanswered, mostly about the whole infection) in my opinion but if you're not too nitpicky, you're going to enjoy it for what it is.