I honestly enjoyed the drama throughout the end, although it lost all its comedy aspect the moment Kang Woo found out Myung Wol's identity and had plot fails and flaws. I felt the story and characters went round in circles and became pretty miserable for the remaining episodes (Kang Woo and Choi Ryu were filled with so much angst it was painful to watch! So sad seeing Choi Ryu smiling face and letting Myung Wol go to Kang Woo too ;_;) but for some reasons, it still managed to keep me hooked and excited about each episode. I was dying to know the outcome of the love square and to be honest, I was afraid they would make it easy by killing either Choi Ryu or Kang Woo. Fortunately, it turned out differently and the ending is somewhat satisfying to me.
Considering the ending, the car accident didn't make any sense though. Plot twist fail. I first thought it could have been a way to fake death for both spies to get freedom from North Korea but didn't Kang Woo had all the information that would make Myung Wol free from both countries anyway? They're super spies so it's true they could have got out of the car before it exploded but someone needs to explain me how they did so in the 5 seconds lap exactly. And didn't Kang Woo called an ambulance when he saw the crash? Didn't they notice the bodies were missing? And how could that North Korean sniper know where the car would be? Too much non-sense.
If it were me, I would have also make Myung Wol come back to Kang Woo at a different place. I understand they wanted to make it look like the beginning and thus having the "starting all over again" feeling but having them meet at the airport didn't make sense again since nobody was supposed to know Kang Woo's departure time (but again, it might be a North Korea thing to know stuffs nobody knows about XD). You know what? Since Myung Wol used to sneak in and out of Kang Woo's house, don't you think it would have been more romantic if she came in her bedroom and suddenly voice over the "I love you" recording Kang Woo was listening a bit before he departs and give them an intimate reunion?
One last thing, I liked the part where In Ah finds the scarf on her car and Choi Ryu watching from afar but I would have left out the marriage scene. It feels like a repeat because of episode 16.
