Spoiler alert.
For me, a good movie is when you still think about it long after you watch it. I definitely still thought about this movie weeks after. First off, the acting of the two main characters is simply superb. Kyungsoo's acting, and the story line, perfectly illustrates the horrors of losing everything before life have even begun. You can feel the frustration and desperation of the main chatacter. and unlike most "depressed" characters in cinema, you really understand how he is depressed.