Revealing mistake: At the beginning of the "Day 50" scene, there is a shot of the "human" meat thawing - in the top right of the screen, a pig snout is visible. (01:13:00)
Suggested correction: There is no pig snout. That is the end of a sleeve that has meat in it for their trip.
Continuity mistake: After 70 days in the Andes, Nando has not grown a beard. Two days later, when they come with the choppers, he's managed to grow quite a nice one.
Suggested correction: It's possible that Nando continued shaving (offscreen) while they were living at the plane, but gave it up (or left his razor behind) during the trek out of the mountains. In real life, some of the survivors did shave while in the mountains.
Factual error: Most of the time the boys have no visible breaths, even though they're in a freezing climate.
Continuity mistake: In the scene when the expedition of 3 finds the tail of the plane you can see an extra set of footprints in the snow when the team arrives. Who was the 4th person walking to the tail?
Factual error: While debating when to begin the trek across the Andes with Nando, Roberto remarks that "winter will be over" soon. This incident took place in South America where the seasons are opposite from the northern hemisphere. The plane crashed in the spring and Nando and Roberto reached Chile by foot in the summer.
Revealing mistake: When Roy digs out Antonio in the snow, you see his mouth move although he's dead.
Revealing mistake: When the guys drag the one dead guy out on the sleigh, you can see his stomach rise and fall slightly.
Revealing mistake: When Antonio cuts into the human meat, the 'chunk' he pulls out is obvious shreds of steaming chicken with tiny brown spots, than frozen human flesh.