Lost in Translation: Played in two ways. When Oh Dae-Su is released from his prison, he talks to the gang of kids and they act like they don't understand him. The movie was set in a time period when the Korean language had drastically changed over those fifteen years and Oh Dae-Su is speaking a very different dialect than the modern one. Unfortunately, this was lost in the English subtitles.
Under Age Casting: The actor who plays Lee Woo-jin, Yoo Ji-tae, was born in 1976, while a scene in which his character is a teenager takes place in 1979.