well, I get it reading it forwards but going back didn't make as much sense? I did try reading it from bottom to top and also just top to bottom from the last page. I guess reading backward, the story is more about a philosophical question: who is the real you, the one shown to others or the one you show others or is the real you something more simple by just physically exposing your body to others.
mangaka def has a lot of skill though, I assume the lack of understanding the story backward has more to do with the translation rather than the mangaka's writing.