Revealing mistake: Anytime there is a fight, the hits hardly come close to making contact, but the sound effect is still there.
Revealing mistake: When Frank kills one of the rattlesnakes with a ski-pole in the RV, you can see that he is just stabbing the floor and not the snake.
Revealing mistake: The caboose and two bunk cars are uncoupled and sent rolling down the hill, with troops locked inside. As the cars roll off a cliff, troops can be heard yelling. However, as the cars hit the ground and shatter into rubble, the wood does not appear to be blood stained, nor does there appear to be any sign of bodies in the debris. The cars were obviously empty for the scene, and given the circumstances of the soldiers allegedly trapped within them, it's unlikely that any of the soldiers could've gotten out in time.
Revealing mistake: Walter and Joanne have two little girls at the beginning of the film, but then much later, there are suddenly two young boys seated at the table during breakfast. (01:17:00)