The Coming of the Quantum Cats can - given different social conditions - develop completely different character traits (timid or assertive, benevolent or predatory, etc.) The title refers to the famous thought-experiment known as "Schrödinger's Cat", where the outcome of a real-world event depends on a quantum event. By some interpretations, the real-world object, in this case a cat, must be in two states simultaneously until it is observed. However, the story is more closely related to the many-worlds interpretation of quantum mechanics where all possible outcomes of an event occur, each in its own parallel universe. The same concept was treated, somewhat more pessimistically, in
Dead or Alive 2 create a physics engine dedicated entirely to the animation of the female characters' breasts. "Dead or Alive 2" used the song "Exciter" by Bomb Factory in its opening sequence. Also used as a background track was "Deadly Silence Beach" and "Clumsy Bird". Both tracks can be found on the self-titled mini-album "Bomb Factory" and on the "Dead or Alive 2 Soundtrack". Two soundtrack CDs were released in 2000 by Wake Up in Japan: "Dead or Alive 2 Original Sound Trax" (KWCD-1001) and "Dead or Alive 2 Original Sound Trax" (KWCD-1004). Several Japanese guide books for the game were published by