Character mistake: The menu selection screen on "Mother" has "L. ALLIGNMENT" mis-spelled. (00:08:55)
Character mistake: While entering the atmosphere of LV-426 when the ships starts to shake in a turbulence, there is a close-up at Ripley's screen showing the terrain and at the bottom of that screen we can see "WEYLAN YUTANI NOSTROMO 180246." The correct name of the Company is WEYLAND YUTANI and Nostromo's registration number is 180924609. (00:16:35)
Character mistake: When the crew come upon the space traveler in the derelict space craft one of them says he is fossilized. For fossilization to occur the tissue must be replaced by minerals from surrounding materials. That is why fossils are found in the ground. When the creature dies it must be covered with dirt or mud before it decomposes. Over time the minerals in the dirt replace the tissue. But the space traveler is sitting in the pilot chair, completely open to the environment and not covered with anything. The term they should have been looking for was 'mummification' or perhaps 'skeletonization'.