Gakuen Sodom: Kyōshitsu no Mesudoreitachi

The protagonist of the game is a teacher in St. Marianna Girls High School, which his sister also attends. One day, a maniac breaks into the school, and, holding the protagonist and the students at gunpoint. He then holds them hostage and forces them to perform violent and humiliating sexual acts with each other. The whole story of the game is basically a long stretch of such acts, while the maniac (and the protagonist) have to deal with new situations, such as arrival of police, journalists, etc.

The gameplay consists of making decisions. Every situation offers a limited set of timed choices to the player. For example, he can have the protagonist to obey everything the maniac says, beg his mercy, choose a victim, choose concrete actions to be performed with the victim, etc. However, the game's structure mostly requires the protagonist to do the awful actions one way or the other, because most attempts at disobeying the maniac's orders result in the protagonist's death.