Darren McAree went through two hours of make-up to be transformed into The Demon (it was originally going to take four hours). It took just over an hour to apply the 'Jack' make-up.
The second day of principal photography was set back over two hours due to poor weather and equipment failure whilst shooting a scene in a field. The scene was ultimately cut from the end of the film.
The film originally opened with a stark montage of the location and of Jack, to introduce and set up the place and the character. This was later replaced by the overdose in the kitchen sequence, though a couple of the montage shots remain as Jack wakes up in the hospital.
There is one shot in the film that is actually taken from the documentary footage that was shot during filming. Andrew Davidson refuses to tell documentary maker Ross Lucas which shot it is.
The Demon is seen wearing the same clothes that Jack wears at the start of the film during the overdose scene.