I noticed something, if you listen at the soundtrack called Scattered Flowers at 3:06 you can hear an odd sound that sounds like Chibimoth. This is in any version of the song I've heard.
It is the song that plays when Chibimoth dies.
Chibimoth's death was for me the saddest moment in this VN.
Nothing made me cry as much as this, the only things that came close were Sakuya 's sacrifice, Panil & Gil's death in Chihaya's route, the ending of the Moon route, and when Kotarou met the little Kotori in Terra.