More than 50 gallons of blood was used in the production.
During principal shooting, the temperatures were well over 100 degrees, peaking at 110 degrees. All the sweat is real.
Theatrical audiences yelled and screamed at the movie so much that the filmmakers included an "audience reaction track" on the DVD.
On the DVD audio commentary, Barsuglia reveals that the guns in Hauser's introductory scene are from Hauser's personal collection. At one point, after Hauser moved, he called Barsuglia, leaving the message, "I've got a problem. I don't know where my guns are."