YU-NO: Kono Yo no Hate de Koi o Utau Shōjo

Yu-no: A Girl Who Chants Love at the Bound of This World is a 1996 visual novel adventure game developed and published by ELF Corporation. It was originally released as an eroge for the NEC PC-98 Japanese home computer and later ported to the Sega Saturn and Microsoft Windows platforms without the sexual content. The story follows the protagonist travelling between parallel worlds to solve the mystery of his parents' disappearance. The game uses concepts from science fiction, physics, mathematics, philosophy, history and religion to construct its fictional universe.