Kamaitachi no Yoru (かまいたちの夜 lit. "The Night of the Sickle Weasels"?) is a sound novel developed and published by Chunsoft. The game was first released on November 25, 1994 for the Super Famicom. It became available on the Virtual Console in February, 2007 for 800 Wii Points. The story-line was written by Takemaru Abiko and production was directed by Kazuya Asano and Kōichi Nakamura.
Kamaitachi no Yoru was the second sound novel developed by Chunsoft, and its popularity brought a myriad of other companies to develop similar games. The term "sound novel" was originally a registered trademark of Chunsoft, but is now regarded as a whole genre of its own. The game sold close to a million copies (including remakes and ports), making it a financial success as well.
The game revolves around Tōru and his girlfriend Mari, who are suddenly drawn into a horrible murder mystery while on vacation at a skiing lodge. The first part of the games develops as a crime-solving adventure. Additional murders occur if the player is unable to find clues, and the story culminates into a horror movie-esque ending.
When the player completes the main story with a certain number of different endings, two additional stories (the occult chapter and spy chapter) are unlocked. When all three stories are finished with every possible ending, two more self-parodical stories also become available. Fulfilling one final requirement allows the player to unlock a parody of Torneko no Daibōken: Fushigi no Dungeon.
The additional stories cover a wide variety of themes, and are completely unrelated to each other and to the main story. Though the same set of characters is used throughout the game, the character settings differ significantly in each story.
Source: Wikipedia, "Kamaitachi no Yoru", available under the CC-BY-SA License.