I watched this a while back on crunchy roll 2 or three years ago. Its a very amazing storyline of how one of the character thinks he is superman and ended up being recorded for a documentary by the main character Song Soo-jung its a amazing movie which made me cry and laugh on the things he does. And how Song Soo-jung ends up showing the character "superman” and how "superman" tries to help the world.
It has an amazing ending which it doesn't tell you how he ended up portending to be superman and leaves you hanging on until the very end of the film.
I suggest you watch it and hope that you may be able to find it somewhere else but i hope crunchy roll may get the movie back in the near future.