I've come across many good analysis of ORV the past few years, and I can't pick which one to pin on my profile. If you're interested, check them out! Some of them may just be small excerpts of people's opinions, though :)
(This will be continually updated!) The Relationship Between Sooyoung, Dokja, and Joonghyuk; Self-Sacrifice As Their Love Language
Han Sooyoung and Kim Dokja's Relationship To The Apocalypse (short)
ORV's Epilogue (short)
Kim Dokja's Story Fragments (short)
Personal Intrepertation Of ORV (short)
TWSA and Kim Dokja
YooHanKim and Sooyoung's Importance (short)
Kim Dokja's Tragedy
Yoo Joonghyuk's Contradiction
Kim Dokja's Tendencies; The Thin Line Between Self-Sacrifical and Suicidal
Us As A Fragment Of Dokja (short)
Kim Dokja Is Fucked Up (short)
Dokja and Sooyoung's Special Bond (short)
Han Sooyoung's Paradox (short)
I'm well aware most of these analysis are only towards the trio of the novel.. I wish we can see more of the other characters :(