Continuity mistake: When Blair asks Mitch "why aren't you answering me?" he says he got a weird message from Laura Barns. Blair replies "that's not funny" and Mitch replies "I'm serious." Then Blair gets a message from Laura, and when she switches back to Mitch's conversation, the last two entries, "that's not funny" and "I'm serious" have disappeared. (00:10:50 - 00:12:30)
Revealing mistake: Throughout the film, the base station radio is not connected to an antenna. In many lengthy shots of the back of the radio we can see the power cord trailing out the back of the unit, but there is nothing plugged in to the antenna socket. This is especially annoying because base station radio problems are a key plot point.
Continuity mistake: On the airplane, the shark bites off April's hand at about the wrist area, but when Fin pulls the gun in April's hand out of the dead shark, the severed limb is an entire arm up to the elbow.
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: The movie depicted the use of obstetrical ultrasound. While ultrasound was first "perfected" in the late 1950s, it wasn't used in British hospitals until the 1970s and not in US hospitals until well into the 1970s, well past the setting of the movie in the 1960s.
Factual error: At the diner scene at the Gimli Slider, there's an ashtray with a lit cigarette on the table. Manitoba has had a smoking ban in all enclosed public spaces for over a decade.
Factual error: The corpse's head in the cafe changes position between shots. (00:34:00 - 00:35:00)
Plot hole: Towards the end the Rich Purgers call for reinforcements, and Shane, Leo, Eva and Cali are hiding behind a wall. A guy somehow opens a door in front of them (without being seen by the three facing him), exposes himself and shoots only Shane, numerous times, to cause his death. He should have been spotted by the people looking in his direction. Also, if he was that well hidden he could have simply sprayed the entire group. He unloaded 5 or 6 shots to Shane's chest...when he could have taken them all out.
Continuity mistake: The girl that Jesse brought into the house, Penelope, was wearing a blue skirt with leggings when they arrived at the house. However when she walks around the corner to take off her shirt she comes back with just black leggings on.
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.
Visible crew/equipment: In the scene after Petyr's death, Deacon is standing in front of a table and the window directly above the table is shown. At that point, you can see a boom mike being yanked out of sight. I know this is supposed to be a docudrama, but this is the only place equipment is shown in the entire movie.
Suggested correction: You said it yourself, it's the boom mic of the documentary crew. They make no attempts to hide the fact that it's a documentary.
Other mistake: When Jordan drops Rusty's truck into the compactor, the excavator and its claw seem just too small for the job. You can see the truck has been sawed shorter as the truck's rear axles stay on the ground while the cab goes in the compactor. There is no possible way for the truck to snap in half like that when lifted. This small excavator would just simply have flipped over trying to raise the truck by the engine compartment.
Continuity mistake: Chilling on the couch watching a movie, Jay's friend farts. Obviously well practiced in the discipline, it takes her merely moments within the same shot to perform the necessary adjustments after the emission and place her index finger back on the dainty seashell lid of her media device. But in the next shot, as she proudly smiles basking in the warm glow of her successful feat, her finger is off the lid. (00:07:00)
Revealing mistake: At the end when April and Kyle are killed, they are thrown in a hole back first. When they are shown, they are neatly positioned beside each other. April even has her knees bent up and Kyle has his arm around her waist meaning they obviously positioned themselves for the final shot.
Revealing mistake: When the girl gets her head cut off with the barbed wire, when her body falls to the ground, her feet bounce around like rubber.
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.
Continuity mistake: At the end when Sarchie is hugging his wife, in one shot the bandage on his arm has unravelled. In the next, it is neatly wrapped.
Continuity mistake: The students' 3rd game is Kagome with 4 Kokeshi dolls. The pink doll starts to the right of the first student to play, the dolls move in a circle around him, she passes in front of him and by the end of the shot she is near his left. The Kokeshi dolls all move backwards between shots and the pink doll passes in front of the student again. After this, she takes 7 seconds to move about 100° despite nobody slowing down and she took that amount of time to move about 170°.
Continuity mistake: Carrie's height changes constantly.