The original story comprised of an additional 15 minutes of material and two other characters. They were ultimately dropped due to time constraints.
The dream sequence of Anna tied to the tree was in fact part of the original story, in which the others had to rescue the cars keys from the zombies clothing, in order to leave the house.
This section of the story had to be hastily rewritten on the day of filming due to major sound issues on set.
Filmed over 3 days.