there are 2 types of dramas, character driven and plot driven, and this was neither..
the characters were not "strong" enough, they didn't have that much personality outside their plots.. beside that early dart scene and the fact that nana was strong willed against her male coworkers, they didn't give her enough... depth? same thing with Jang Ki Yong or the other characters, there was always something missing...
and the main plot was so overused that it was not enough to carry this show, the only thing that did was the fact that
Soo Hyun was a hitman...

+ nana proved herself as a competent actor
+ nana's beauty, I did consider her pretty before this drama, but there's something extremely beautiful about someone acting so well, or singing and other jobs, as long as they try hard, you know? ;)
+ Jang Ki Yong was made for this role, his eyes were everything
+ the filming was well done, everything looked pretty and high quality
+ really nice action scenes, nana's fighting scenes were the best ;)
+ ep12, I think that's the only good ep...
- it was reeaaaalllllly draggy, I mean like they only needed 2 to 4 eps max.. that's the problem with 12 eps drama, it's like the production team didn't think the plot's worth 16 eps, but they still want to drag it out...
- I skipped alot, to the point that I didn't even care for the 2 main leads parts, but I still got everything thanks to ep12 ;)
- a drama that focuses more on the old villains talking is always a horrible, I don't even know what they are talking about for that long.....
- I feel like the start and the characters relationships were rushed because they were worried 12 eps won't be enough for character growth... so that means bad time management?
- horrible weak repetitive plot. no mystery and not much thriller (I'd have given the story a 1 if it weren't for Soo Hyun's "job")