*SPOILER* I still think it is about drug. Specifically, probably about heroin (or another injected drug). When they "first met" there was a song playing, which is far more common when taking drugs than when self-harming. There is also an implicit encounter in public, and in the park, that would also be a lot more expected in consuming drugs. Finally, he has visions (when the girl becomes distorted), which occurs when taking certain drugs, and not when self-harming. Whatever the metaphor is (if there is even one), I think this game is completely great, and I want to thank the creator!!