The tracking shot of fire racing down a trail of kerosene towards the camera was shot in reverse, with the DP Ryan Harris literally running through the flames.
While Producer 'Michael Elkin' and Director John Michael Elfers were set dressing an abandoned house on Christmas morning, they got held up at gunpoint by police who mistook them for burglars.
Director John Michael Elfers stunt-doubled for principal actors, even dressed in drag with his legs shaved.
All the SFX were achieved in-camera (no CGI), melding techniques from early film magicians, like behind the lens filters, two-way mirrors and speed ramps.
The old church that explodes in the climax actually caught fire and burnt down a year after shooting.