Based upon the novel Animas by José Ortuño.

In the hospital scene, after Abraham's dad has been hit by a car, a child can be seen in the background dressed like Freddy Krueger; they're also seen in a very quick close up during the flashback at the end of the film. There are some tentative similarities between the dream worlds in both films, and the horrors that can be found within them.

In every scene they're together, Bram is on the left side of the screen and Alex is on the right side.