Boxing is used in this movie as the main plot, but this is not a Rocky episode and the protagonists do not fight for glory, fame or wealth. The climax match is just for the domestic rookie contest title and even a win would not improve the life of either Kang or Ryu that much. Boxing has long been dying as a professional sports anyway, at least in Korea.
So what these two main characters fight for? They are just trying to regain the minimum dignity as a human being, the last desperate effort to climb up from the deepest bottom of their existence. Therefore, you know, sometimes who wins is not so important.
This film was not a big hit when it was released to Korean theaters, and no wonder it was as the majority of movie consumers are happy youngsters.
Many of them think this is just another tear-jerking melodrama. It is not, I guarantee, but you would not be able to appreciate the real thing unless you have once gone through your own hell in the life. I cried with Ryu at the end of the movie, I felt his sorrow and happiness so real just as they were mine, it was mentally painful.