After Sonny and Candice arrive at Donald's cabin, Donald is serving scrambled eggs to his guests. While he is serving, he has four bullets on his vest on his right-hand side. After turning around to return the pan to the stove, he is missing one bullet.
During the robbery, the teenagers remove their jackets just before the gunman moves to the counter and tells the old man on the till to join the others. In the next shot, when the old man joins the group, the teenagers can be seen removing their jackets again.
When Sonny's car goes over the embankment the car is buried up to the doors in snow. A few minutes later the snow is flat - packed down by dog sleds and vehicles. The car is able to be freed and driven away. Unfortunately, the spinning tires are screeching like they are on dry pavement. Tires on snow and ice do not make this sound in real life.
When Jack pulls into the survival camp driving a BMW, He sees Donald armed on the sled, so he stops and backs up. The car he is driving when backing up is a Cadillac, not the Bimmer.
During the robbery scene, the hammer on Jack's pistol alternates from being cocked and uncocked before he pulls the slide back.
When Donald shows his new "Assault Rifle" to his fiancé, he tells her it's "308 caliber with a... *snaps stock open* Folding stock". In fact, it's not. Donald's rifle is actually a Finnish Valmet Model 76 chambered in .223/5.56mm. While the Valmet 76 was available in .308/7.62 NATO, Donald's rifle is clearly, as noted by the size & shape of the magazine, the .223/5.56 model.
At the gun store, one woman holding a .44 revolver rolls her hand down the cylinder to spin it around. (The revolver's hammer is down at the time.) You can't spin a revolver's cylinder that way -- the working parts that move the cylinder and hammer are engaged. The cylinder won't spin freely.
If Jake is traveling from New York to Vermont, he would have no need to travel through New Hampshire to arrive at his destination.
In the closing credits, the title for three assistant directors (Joseph Reidy, Bill Elvin, and Louis Race) is misspelled as "Second Assitant Directors."
When Williams is escaping on a dog sled, Reed is chasing him in a BMW, but when the camera shot is inside the vehicle it's a Cadillac.
After Sonny starts driving the taxi,and picks Jack up as a fare, you can see what appears to be a person in the back seat of the taxi just after Sonny starts driving.