Normally, I'd be okay with this type of shift, but these characters are both so dull that jumping between their narrations is unnecessary, distracting, and pointless.
And, really! How can a spy be so uninteresting? Even her mission lacks everything that makes a spy intriguing... there's no danger, no mystery, no suspense. This is a movie, isn't it? Even if spies aren’t that interesting in real life, writers and directors are allowed to ‘spice it up’ for entertainment’s sake, right? I mean, there’s only so much espionage that can go down at a Burger King...
For a majority of the movie, she’s so wrapped up in her boring undercover-role that we rarely get to see her being kick-ass and cool (something She's On Duty accomplishes continuously and without effort). I think she goes into spy-mode perhaps once or twice throughout the entire film… and even then, its not impressive. She’s a good actress (I’ve seen her in several other things—including the drama, Taste Sweet Love/ Snow White) but in this movie, she really doesn’t have much to work with.
(If spy movies were always depicted this way, I think the espionage profession would dry out.)
As for the romance… I’m truthfully at a loss… there was no chemistry whatsoever. This alone is very rare, since Gong Yoo is known for making his co-stars shine when it comes to romantic scenes (of course, this film didn’t really have any, so it’s not really his fault). We’re talking about a character whose entire idea of romance involves buying his girlfriend a tube of lipstick… and then telling her shyly that he wants her to put it on and then kiss him. I just found that weird and almost fetish-like: next thing you know, he’ll tell her he just wants to smell her feet…
Gong Yoo is SOOO much better when he’s playing a cool character, like in She’s on Duty. Here, Go Bong (his name being one of the only funny jokes in this movie) is so average and uninteresting that anyone could have played him. Don’t get me wrong, the acting here was still great… but the characters, the script, the directing… everything was so bland, it didn’t matter. Nothing could have saved it!
It’s a great concept… just horrible execution.
So in conclusion, don’t waste your time with this movie.
There are many more just like it that are better written, have interesting characters, and involve an actual plot. If you’re a fan of Gong Yoo and just want to watch this for him… go ahead, but don’t expect to be constantly swooning. The opening scene alone shows him on a toilet, taking a dump—and not many of his other scenes will make your heart race, if you know what I mean. Though he does look cute when he's dressed like a spy. ^_^