Revealing mistake: When the needle is set in the pool of water in a stump to act as a compass the pool has been carved out with a chain saw very recently and clumps of the wrong moss set around the rim like it belonged there.
Revealing mistake: In the last scene, when Anthony Hopkins and Alec Baldwin are trying to kill the bear, they appear to have sharp wooden spears. As the camera angle changes you can notice that Hopkins is holding a green/brown training pole instead of a natural wood spear.
Answer: That would only work when the sun is visible. In Alaska there are frequent rainy and overcast days where the sun is completely blocked by heavy clouds, making a precise directional determination difficult, if not impossible.
raywest ★
They could see the sun; it was a sunny day after the crash, and the next day they were able to see the North Star. To begin with, they had great visibility, and it seemed easy enough to find a mountain peak or pass to use as a quick reference.