Factual error: During the decompression the plastic water bottles crush. The opposite should happen, as a decrease in external pressure would cause the bottles to expand.
Factual error: In the first scene of the film the girls are shown in a flashback playing with the Ouija board. When one of them holds the planchette up to the other one, the underside of it has text saying "© 2013" molded into the plastic, even though the scene is based years before that. (00:01:20)
Factual error: Writer/director Adam MacDonald boasted that he studied black bear predatory behavior and black bear attacks on humans for years in preparation for making this film, because he wanted to depict a black bear attack in as factual and as authentic a manner as possible. But, at the most crucial point in this film (when the black bear actually does attack Alex and Jenn), factual accuracy goes out the window. As Alex and Jenn cower in terror, the bear lunges into their tent and bites into Alex's leg; whereupon, Jenn fires a can of bear spray (a stifling pepper-based chemical) point-blank into the animal's face. The startled bear retreats for a moment, but then lunges into the tent again, dragging Alex outside and killing him; thereafter, the bear continues pursuing Jenn for the remainder of the film. However, according to years of extensive study by the University of Calgary, no bear has ever attacked a human after the animal was sprayed with bear spray, much less resumed an attack, as depicted in this film. To date, the success rate of defensive bear spray is 100%. So, the factual accuracy of "Backcountry" was abandoned for the sake of cheap thrills.
Factual error: Scarlett and George use the Rose Key to translate the inscription on the back of Flamel's ancient tombstone, and it translates into a rhyming English lyric puzzle. Problem is, they are translating this lyric puzzle from Aramaic (an ancient and virtually dead Middle Eastern language) to modern English. Aramaic would not and could not translate into rhyming modern English.
Factual error: The alien drops the video camera out of the UFO from outer space and it falls to earth landing on the ground. This very far drop would certainly have busted it to pieces, if not ignited it on reentry, but when the guy picks it up off the ground, it appears only the screen is cracked.
Factual error: Just like in the previous movie, Herzog is referred to as "colonel", in particular in the WWII museum where Martin reads about his history. But both in the museum's picture of him, and throughout the movie, Herzog is wearing the uniform of a SS Standartenführer. To hold a title of Oberst (colonel), he would have been a member of the Wehrmacht, regular army, not SS.