マレビト～そして世界は色を失う～

1980s. Main character Kensuke lives a normal school life and prepares for a cultural festival. However, one day he starts to see a mysterious man hiding from him, and that changes his peaceful life. He remembers tales of Marebito which is either a production of unshaped human fantasies or a demon. Will Kensuke get it all from his youth or get trapped in a strange incident?

[From vndbreview]