The movie uses two different animation styles: 3D animation to represent the present, and traditional hand-drawn 2D animation for the flashback scenes. Since different companies were used for each flashback several different styles of 2D animation are used, giving a different look to each of the flashbacks.
If you look closely, the Holographic Game that is seen being played is Dante's Inferno. The same developers who made the Dead Space games also made Dante's Inferno.
The holo-game being played in the movie is actually another EA game release called Dante's Inferno.
When the film was released on DVD in New Zealand, it was given the Restricted 16 rating. However, when the film was broadcast on the Sky Movies Extra channel on Sky Television in New Zealand in 2019, the rating was changed to Restricted 18.