Continuity mistake: When Nicholas Cage is being escorted to fetch the roll of film from his car, there are a few scenes where the accountant is holding a gun to Nicholas's head. When the camera is directed at the accountant, two hands can be seen grasping the gun, but when the camera is facing Mr Cage, initially there are two hands but after the next switchback there only appears to be the one! (01:20:50)
Continuity mistake: When Nick Cage picks his daughter up to stop her crying at the beginning of the movie, he rests her head on his right shoulder. But when he turns around to tell his wife that he loves her, her head is now resting on his left shoulder. (00:06:10)
Continuity mistake: After Machine cuts Max's throat, Welles runs toward him and is thrown down by Machine. Then the shot cuts to Poole (Gandolfini) kicking Welles with Machine running up. Then a shot or two later when Machine and Poole are beating Welles it cuts and Poole is kicking Welles and Machine is not around. (01:22:10)
Continuity mistake: When Dino is burning the film, Welles is handcuffed to the bed. However, his handcuffs move from the outside the first T of the bed to between the first and second Ts on the bed. (01:22:35)
Continuity mistake: At the end, in a fight with the machine, Nick Cage sees his gun outside the fence. When he reaches for it, now it is a knife, and after he retrieves it, he now has the gun.
Continuity mistake: When Tom and Eddie get to the building where Mary Anne was killed, it's dark outside, yet when they walk through the door, it appears to be daytime.
Continuity mistake: After Tom has broken into Machine's house and begins to go up the stairs from the basement, we catch a quick glimpse of Tom's pistol. The pistol doesn't have a silencer, but, as he begins the climb up the stairs it suddenly appears. (01:50:20)
Answer: A snuff film is a movie where someone is actually killed on film, where the intention is to sell the movie afterwards. There are several other instanses where people are shown murdered on film (news reports, the Zapruder film, dictatorships documenting executions, etc.), but if the purpose of making the movie is not commercial, it is not a geniune "snuff" film. FBI experts and other law agencies state that they have never seen a genuine "snuff", and that it is most likely just a rumor, especially since the concept of someone willingly selling evidence of their own crimes to strangers and remaining undetected for 30 years, is highly unlikely. See http://www.straightdope.com/classics/a5_258.html for more details.
Twotall