Not just Korea. I felt like it was making commentary on society on a global scale. I thought the most interesting thing in the whole show was how everyone was there by choice. They technically didn't have to play the game, but everyone knew that basically they did. It was a thinly veiled criticism of capitalism.
I would definitely say global, and not just applicable to today, either. My grandfather whom I have never met because he died while my father was still in HS could have very easily have been a character in this show, at least from the stories I heard about him, and not just from my father. He was much like the main character, only much more abusive toward his family. As such, he'd never be able to make it through the first episode (he couldn't even make it through the movie Hardball) - then again, with his life experiences that's understandable.