Continuity mistake: When Jerry and the Dr. are talking in the tent the first night on the way to the mountain, the Dr. shows Jerry a notebook with a picture of his wife and son. Jerry hands the notebook back twice in a repeat of the same shot.
Continuity mistake: When Maya goes to lasso the Doctor after he fell through the ice, her left paw is through the loop in the rope, but when it cuts to the Doctor and back, the loop is shorter and horizontal.
Continuity mistake: When Jerry meets Dr. Andy Harrison at the "convention" and they pick up drinks, notice Jerry's beer mug. The head on the beer suddenly reduces between shots as they go to the table.
Factual error: Winter in Antarctica begins in June and ends in September. The movie says winter is beginning in February which is incorrect in the Southern Hemisphere.
Chosen answer: Yes you missed Old Jack, who's too old to go with the others on their journey and dies at base camp.