Turned into a feature after Paul Solet's 2006 short film of the same name (starring Brian Austin Green and Liza Weil) generated positive buzz and awards.
The Matheson family is named for author Richard Matheson, who is most famous for his vampire novel I Am Legend.
The family cat is named Jonsey, most likely after the cat in Alien.
Adam Green: Horror director Green (Hatchet (2006)) is in the supermarket scene as the employee selling meat. He's the producer of this film.