Roberto Canessa is shown sitting beside Nando Parrado in the rescue helicopter. Canessa never made that trip; he was by that point so debilitated by the dysentery he had battled for much of the trek over the mountains that he could no longer walk.
In the movie, Nando Parrado gives one of the little red shoes, purchased by his mother for her grandchild, to Eduardo Strauch. In real life, he gave the shoe to Carlitos Páez.
In reality, the plane tail was ripped off by the torn-off right wing which had clipped a mountain peak before. In the movie, it's the tail clipping a mountain peak and then being ripped off.
The real life counterpart of Federico Aranda (Rafael Echavarren) died on the 37th day.
In the movie, he is seen alive until the 50th day.
The aircraft is shown to have a ground proximity warning system but these were not made mandatory on aircraft by the FAA until 1974. Two years after the films events take place.
The narrator (played by John Malkovich) is supposed to be an older Carlitos Paez. The narrator not only looks nothing like the guy who played the younger Carlitos (Bruce Ramsay), he also doesn't have an accent like the younger version.
When the avalanche first hits, the actors have clearly been swapped out for mannequins.
When one of them find the tail of the plane the other two are still on the ridge. As they run toward him the camera is now behind him revealing two sets of tracks in the snow, but the other two have not tread on the snow yet. Clearly a re-shoot in the same location.
When the crew member offers tea to the pilots, they accept. But what the guy actually brings to them is "mate" a drink typical from South American (and especially Uruguay and Argentina), made from a tea-related plant. No actual Uruguayan or Argentinian would ever call it "tea".
Towards the end of the movie (when they first start to enter the green valley), the helicopter has a long pan down a waterfall. At the start of this scene there are two people sitting on the large rock at the top.
At two different points, a safety cable can be seen attached to 3 of the actors. Once (at around 1 min) during one of the first expeditions to find the tail of the airplane there are 5 walking. The glacier collapses under the feet of the lead boy, leaving him dangling off the edge of a crevasse. The cable pulls up from the snow just under the actor as Canessa and the others pull him back up. The second time (at around 1h 45 mins) is when Canessa slides off a rock, just as they are reaching the top of the mountain. Nando attaches a safety belt from the Fairchild to his belt and Tin Tin braces himself to lower Nando to Canessa. The thin cable that is hooked to the actor who plays Canessa is partially buried in the snow and pulls up breaking the snow for an instant. You can also see this cable threaded through Nando's left leg of his pants. As the scenes shift, Tintin is sitting on it, and it's also snaked on Nando's left side against the mountain.
When Antonio is scolding the others for eating all the rations, the reflections of several crew members, a lighting unit, and a mic are visible in one of the survivor's sunglasses.
After the plane tail is gone, there are reflections of a studio light in a boy's glasses who sits in the last row. The sky is overcast so it couldn't be sunlight.
The story takes place in the southern hemisphere. However, the sun orientation suggests that they are in the northern hemisphere. Based on what is being described as East and West in the movie, the sun should be slightly to the north during the day, but it's slightly to the south.
In the sequence that briefly shows the moon, the man in the moon image would be upside down since they're in the southern hemisphere, not right side up like in the northern hemisphere as it is shown.
Daniel Fernandez says 8 people died in the avalanche. While this is accurate to the true story, in the film, only 6 people die in the avalanche. Hugo Diaz survives the avalanche in the film and lives to be rescued, even though his real life counterpart, Diego Storm, died in the avalanche. The 8th victim, Juan Menendez, has no counterpart in the film.
One of the survivors insists that another pray. The man tells him that he doesn't pray because he's an agnostic. Agnostic isn't relevant because agnostic doesn't necessarily mean you don't believe in the Christian god. What he should have told him, was that he was an atheist or at least that he didn't believe in the Christian god.