Gaffes

Just before the bad guys ambush Sun Woo in his flat, he is lying on his couch and the clock beside him reads "9:45" , two shots later, we get a close up of the clock as it switches from 9:39 to 9:40.

Toward the end of the film, when Kim Sun-woo is walking down the corridor searching for his former boss, a guard sitting and reading a newspaper gets up to stop him. Kim Sun-woo shoots him but his gun is not pointed at the guard. Rather, it is clearly pointed at the wall where fake blood appears after the shot like a paint gun.

At 1h and 26 min., the weapon smuggler breathes after being shot and killed by Sun-woo. This mistake is also very revealing at 1 h and 28 min.