In the games, Hitomi is portrayed as an Asian-looking girl with German Heritage. In the film, she is Caucasian, but still looks fairly convincing.
In the games, Hayate & Ein are the same person. In the movie, though, they are two different people;
While Hayate is a Japanese ninja, Ein will be a blonde Caucasian young adult who has nothing to do with the original Ein, save for being a German Karate practioner. However, in the middle of the movie, they actually will be connected.
Due to their sibling rivaly soured into spiteful grudge, Kasumi will kill Ayane due to Hayate renouncing their relationship because she prevented Kasumi from saving Hayate (therefore dubbing Ayane the true traitor).
In the games, Christie uses snake Kung fu as her fighting style, but in the film, she will use Koppo-Jutsu to fit in more with her assassin theme.
Scrapped characters, like Fang Fu & Kelly (given the surname Pei) will be featured in the movie.
The Dead or Alive Tournament will be similar in functioning to the King of the Ring Tournament in WWE.