According to Tomonobu Itagaki, the Temple on the Mountain stage was originally going to be filled with human tourists. But, for an unknown reason, the team filled the stage with 108 white monkeys instead (the number 108 representing worldly desires in Buddhist teachings). The lead designer of the game became so inspired by their addiction that he suggested making an all-monkey fighting game.
Jann Lee's 3rd costume is a reference to Bruce Lee as Hai Tien in his final, unfinished film The Game of Death.
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Rachel from Ninja Gaiden makes a cameo appearance in Christie's ending.
Tina's 2nd costume is from a dropped costume design that was originally for Dead or Alive 2.
Tina's 4th costume is an unused costume that was originally designed for Ayane in the concept art for Dead or Alive++.
Series creator Tomonobu Itagaki stated that he spent most of his time during development just working on the game, and spent very little time sleeping (about 10 minutes a day).
This is actually the first retail game on the Xbox 360 to have "Zero Point" achievements, or achievements that do not add to your gamer score. This allowed it to be featured in the 2012 edition of the "Guinness World Records: Gamer's Edition."
Team Ninja wanted to include Master Chief in the game as a guest fighter. However, Bungie told them it was impossible for him to be in the game due to storyline restrictions but they were still interested in the idea of putting a non-cannon character from the Halo universe in the game. The end result was the character Nicole-458. In keeping with the idea of English being the language of the United Nations Space Command, Nicole is also the only character in the game that speaks English.