Kusari

Kusari (鎖) is an eroge visual novel by Leaf. It is a suspense adventure game dealing with psychological warfare as players are pitted against a cunning and powerful criminal while trapped in the open sea on a cruise ship.

Although this game produced Leaf, much of the staff for this game was outsourced. This was due to the fact the game was outside of the fantasy or true love scenario games that have become the company's backbone. Instead the game had twisted dark scenarios.

As the game's story progresses, game play revolves around the player making the correct selections and collecting items. If the wrong selections are made, or an item missed, the story will eventually conclude abruptly with death and game over. The goal is to kill the criminal on board, which may happen in one of 9 different endings in the game. These multiple endings range greatly, from a happy ending, to twisted bad endings.

Story
The stage of this tale is set inside the high speed experimental ship "BaShiRiSuKu". Kyosuke Koduki, the game's protagonist, is invited on the ship's maiden test voyage as a guest by his friend's mother. When the ship finds castaway Yoichi Kishida, things go horribly wrong for the voyage.

Characters

 * Kyōsuke Koduki (香月恭介) : The male protagonist of the game. A high school student who has lost his father at a young age. The tender-hearted elder brother of Chihaya, and reliable guy among his friends.
 * Akeno Orihara (折原明乃) : A long-time childhood friend of Kyosuke, and daughter of Shino. A gentle girl with strong convictions.
 * Megumi Katagiri (片桐恵) : A reserved and precocious girl. Because she tries hard not to display her feelings, she is hard to read.
 * Karen Ayanobe (綾之部可憐) : The eldest daughter of a noble family and sister of Tamami. A brash elitist with a large ego.
 * Tamami Ayanobe (綾之部珠美) : The younger sister of Karen, although she is only one year younger than her sister, she looks and acts many years younger. Despite her immaturity and propensity to play pranks, she is quite clever at MacGyver-ing items.
 * Chihaya Koduki (香月ちはや): Kyosuke's younger sister. Although constitutionally weak, she is very strong-willed girl, because of the loss of her father at a young age. Highly attached to her brother.
 * Tomonori Hayama (早間友則) : Kyosuke's best friend by circumstance of sharing the same interests. He is very vain and patronizing person, who is very self-centered.
 * Shino Orihara (折原志乃): Mother of Akeno, and the chief person in charge of the "BaShiRiSuKu" voyage. She is the one that invites everyone on the ship's maiden test voyage. A very accepting and generous woman.
 * Yōichi Kishida (岸田洋一): A man found adrift at sea. Claiming to be a marine researcher, he boards the ship, and murders the ship's crew. A fearsome person skilled at psychological manipulation and terror tactics.

Release and sales
Kusari was the fifth top selling computer game on getchu.com for the month of its release, and it was the 44th top selling eroge for 2005. Although these are very good sales overall, they pale in comparison to many of Leaf's other titles, most notably against Leaf's To Heart 2 Xrated which ranked #1 in the same year).

Source code scandal
Kusari was one of four games Leaf was forced to release its source code to the public due to having used the Xvid video codec in the game. XVid is licensed under the GNU Public Library, which requires that programs using the codec to make their source code available to program users.