Revealing mistake: When Wick is rubbing his toeless feet, the shot changes so that the camera is behind him and you can see him still rubbing except now you can see that he is simply curling his toes over.
Revealing mistake: When the expedition is going to pick up the old guy, (I can't quite remember the name) and they are about to land in the snow, you can clearly see that there are already marks from a helicopter.
Revealing mistake: Near the beginning when the bearded guy falls and clamps his leg between two rocks they shake.
Revealing mistake: In the opening shots of the film there is an eagle flying around the buttes. It is an obviously digitally rendered eagle as it is transparent at some points. This is very evident when the eagle passes from in front of a butte to the open sky and it's obviously not a shadow.