For me, the BL aspect is not what's the most important in this film, even if it's in the center of the action.
What I appreciated is the realistic depiction of the highschool life. In an all boys school, the violence is omnipresent between students but also from the teachers. Bulling is simply ignored so one has to do with it or find something to divert the attention to something else.
Actors are not polished at all, at times the environment / ambiance is shady, almost sordid.
This is not your fluffy BL drama but rather a slice of real life (almost like a slap for me) and it basically shows what a gay person may have to endure in the Korean society. This was filmed in 2014 so I jus hope society evolved since then.
But - it's rather well executed, the young actors played wl and were credible. I would probably have appreciated a glimpse of their future. The ending imo doesn't give real closure to the story.
If you hesitate and are not afraid of some violence, go for it.