I was bored for the whole first episode, but halfway through the second it started getting interesting, and by the third I was really starting to like it. Just enough action, romance and humor to make it fun. Never really cared for Anna because she pretty much just wept and cowered the whole time, and was also painfully naïve. However, K2 had a good range of emotion and character development that was fun to watch, from his adorable reactions to a damsel in distress, his skill and leadership, and his complex relationships with both the strike team and Choi Yoo Jin, which were spiced up by his ambivalent, disrespectful attitude.
Choi Yoo Jin was fascinating even from episode one. Very few characters were painted in black and white, and as motivations were revealed it was hard to truly loathe them, even if they did despicable things. It made for great storytelling, and yet the characters’ sins left a few scenes without the poignant impact.
In the end, the only people I rooted for were K2 and some of the smaller side characters. I agree with other reviews I've seen that they made K2 a little too invincible so it became highly unbelievable at times. On the whole I though it was worth the watch, but I don’t think it’s one I’ll be returning to.