This film was made in just 28 days as part of the 28 Days Later Film Challenge.
The films makers Adrian Pinsent and Tim Hunt were given the film title on Feb 1st 2010, not knowing what genre or subject matter they would be dealing with. The film had to be completed by February 28th 2010. The rules stated that the film had to be no shorter than 70 minutes. They finished just 30 minutes before the deadline.
Adrian Pinsent wrote the entire screenplay in just 12 days, handing it to the actors who had just one day before filming commenced to learn their lines.
Principle photography lasted just 7 days.
In the final three days of editing neither Tim Hunt or Adrian Pinsent slept.