SBS released Kook Yoon Su and Choi Ung’s full high school documentary, the viral video shown in the series.
They also added parts of the making of the documentary from the present day.
UPDATE: Saw that the YouTube video became unavailable for viewing in the Philippines and Singapore. (Not sure for other countries, but the video was available last January 25 to early January 26.) So, here’s a new link. 🙂
(Didn’t delete the YouTube one, in case it’s available to other countries.)