12Riven: The Psi-Climinal of Integral is a text base adventure game with a complicated and engaging plot. The players are allowed to view the events in the story through a normal high school boy and a tough police woman's eyes as they work toward rescuing a girl, Myuu, from being killed by a powerful and mysterious psychic.
The game supports a multi-ending system. Although there is one true ending, depending on what choices the gamers have made during the events, the story may result in a completely different way from the intended ending. And it is always a pleasure to view all the endings.