Pretty much a Korean "Bourne movie". Spies, secrets, double agents, betrayal, vengeance, action, you get it all. Solid performances from all the main cast. The writing is a bit of a B-grade but overall production values are top notch.
I got two main problems with it. First one is the runtime. For such a fast paced action thriller, it's at least half an hour too long.
But the main problem is the camera. It's not the usual slightly shaky style to underline the action. Remember the second Bourne movie? Yeah, well, this is worse. Much worse. In most shots, you won't know what's happening at all. They probably fixed a non-stabilized camera on a kangaroo and let him run amok through the city. My head actually started to hurt while trying to decipher what's going on on the screen all the time. Avoid if you're sensitive to these kind of things. It ruined it for me.