Jigsaw (video game)

Jigsaw is an interactive fiction game, written by Graham Nelson in 1995.
The game begins on New Year's Eve of 1999, with the player discovering a time machine enabling them to travel throughout the twentieth century to ensure history unfolds 'correctly' despite the activities of 'Black', a character who starts out as an antagonist but becomes the player's love interest. 'Black' has no explicitly stated gender, allowing players to choose that for themselves.
Jigsaw contains references to other interactive fiction games, including Trinity. Features of the game include attention to detail, and a romantic relationship between the player's character and another central character whose gender is never revealed.
Jigsaw has been described as "acclaimed," "epic...notable," and as " one of the most fun educational games in existence". The gameplay is challenging.