For me, this was so slow. I felt like I'd been watching it forever, imagine my surprise when I was only on episode 5! I stuck it out, hoping it would improve, again, I'm only speaking for myself, it didn't.

There were a couple of positives:
1) Chae Jong Hyeop. He had the great ability to go from nerdy to "spy" in a moment. He did a lot of switching back and forth. One minute he's someone that has no drive, just wants money, then the next he is standing up for the underdog.
2) I loved Im Chul Soo's scene in the last episode when the police asked him what other jobs he's had, and he referenced his characters from other dramas. That was so funny!

Otherwise, too many bad guys, a wasted and useless romance (romance is my favorite genre, but don't try to fit it in where it doesn't belong), lots of repetition, and I'm still not sure how I feel about the ending.