Prismaticallization
Prismaticallization · VISUAL_NOVEL
Adventure, Visual Novel 1999
About this title
Prismaticallization is a dating sim, whose hero is a highschool senior named Shoji. He finds a strange object when he's invited to a summer resort by his classmate Akemi. The object causes him to repeat a day, but seems slightly different. (source: Japanese wikipedia, roughly translated + paraphrased)