Corrected entry: When the film starts you see the bridge and a stack of papers flap in a breeze.The crew are in hyper sleep and don't need oxygen so it's very unlikely they would have their valuable oxygen supply switched on and turned up enough to make a breeze for the 20 months it takes to travel back to earth.
Correction: Who said it's oxygen? It could be any inert gas. Nitrogen doesn't support combustion or corrosion, dissipates heat, and can be easily mixed with stored compressed oxygen in the right proportion immediately to the crew being revived.
Correction: The company that owned the ship intended for the crew (without their knowledge) to be diverted to that planet solely to collect one of the aliens. The ship was programmed to wake them up at a specific time and location and it would make sure that all life support systems were fully functional before waking them.
Correction: This happened before the ship received the signal and so they wouldn't have been woken otherwise.
A ventilation system operating a fan would not use up the valuable oxygen supply. At most it would be wasting a small amount of energy, however if there was no air in the ship, the heat from the computers would not be able to dissipate.
Corrected entry: When the crew split into two teams of three, Ash gives Ripley a movement sensor, which he tells her detects movement in the direction its pointing. However, when Ripley points the sensor at Brett and Parker (who are both moving at the time) it doesn't detect their movement. (01:00:35)
Correction: The motion sensor does not work very well. Ripley even comments on this when she says to Parker "Changes in micro air density my ass." Parker also comments "What's the matter with that box?" when Lambert struggles to pinpoint the location of the Alien while Dallas is in the duct. It has been speculated by some that Ash purposefully gave the crew faulty equipment to impede their efforts to kill the alien.
Corrected entry: When Sigourney Weaver auditioned for the role of Ripley, she had no idea that the part was written for a man.
Correction: None of the roles in Alien were written specifically for a man or a woman. The writers made note that any of the roles could be filled by either sex.
Corrected entry: Ripley's nosebleed: from 1:17:16 (chapter 14: 'A Confrontation with Ash' on the '99 DVD), Ripley's nose starts bleeding, eventually very noticeably. This is almost a full minute before Ash begins attacking her by throwing her twice, which might actually make it bleed. (01:17:15)
Correction: It's just an incidental nosebleed that can occur for any number of reasons like dehydration, blood pressure, etc. In addition to the other answers, it seems the film's purpose with the nosebleed is to contrast a sweaty, bleeding Ripley against Ash, who is totally dry aside from a strange drop of white fluid trickling down his face. The juxtaposition is a signal that yes, Ash is indeed "bleeding/ sweating" this white substance as a body fluid and it hasn't just dripped or spilled on him.
Correction: Actually, Ripley's nosebleed was from when they opened the airlock on the Alien and she and Parker were caught in the decompression. That scene obviously was never filmed but the nosebleed was in reference to it. Also, in a cut scene you see Ripley and Lambert talking with Parker over the intercom where he says the Alien is right next to the airlock, apparently somewhat fascinated with a blinking light on in the door.
Correction: This would only be an error if a later scene were intended to show the moment the bleeding is caused by some physical strike, but there's no such moment (and there is the chance that her first shoving match with Ash may have had her head striking his, but it's not a certainty). Still, nosebleeds are commonly triggered by stress in people prone to them. Ripley's nosebleed begins after she learns of the special order (crew expendable) and becomes extremely distraught- and after her physically tossing Ash around (causing his head cut that later drips). She marches off, and in the passageways she can then be seen with the nosebleed.
You're really rationalizing this. Ridley Scott did not make Ridley's nose bleed to show that she's stressed out. It's inexplicable, and was the result of something cut from the film. The presence of it in the film constitutes it as a mistake.
Accidents and unintended effects are not necessarily mistakes. The nosebleed may have been intended as one thing - a reference to another scene - but became something else by that other scene's absence: a detail that helps sell the realism of the moment precisely because it does not feel contrived. Because a random nosebleed that occurs at an inconvenient time whose cause is not immediately obvious is something most people have experienced at one time or another.
Corrected entry: When the Alien appears behind Brett, we first see its tail lowering before the rest of its body, even though the tail is presumably how the creature was being suspended in the air. Immediately after chomping Brett's head, he and the creature are lifted upwards, again presumably by its tail, though it's not long enough to carry them the implied distance and it's unclear what it has latched onto in the first place. This scene starts a tradition of sorts, as both 'Aliens' and 'Alien 3' feature their own scenes in which an Alien grabs a victim and both are subsequently lifted upwards by a great height, presumably by the creature's tail, and the mechanics by which this is possible and even where exactly they're going off to are always obscured to the point where the creature may as well be wearing a jet pack.
Correction: The alien is suspended from the chains above Brett by its feet and hands. In the Director's cut this is more shown. There are also extended versions of the scene which make it more obvious what happens before and after Brett is bitten. The creature uses the chains to escape to the ducts and those are certainly well within reach of the ground. The scene you refer to in Aliens, in which Dietrich is grabbed, shows the alien using its legs to walk backwards up the wall as it carries her, the tail is not involved. These creatures are shown in all the films to possess an ability to grip walls and other surfaces similar to insects, and they are shown with remarkable flexibility, agility, and strength.
Corrected entry: In the very beginning before anyone is awakened, there is a scene where a computer "wakes up". Between two shots of the computer's console, a coffee cup appears on the right side in the second shot.
Correction: Those were two different screens, one with pieces of paper glued around him, and one is without them. There was a personal helmet in front of each screen.
Corrected entry: The newborn alien that bursts from John Hurt's chest is next seen full-grown, munching on a crew member who is searching for Jones the cat. Assuming that it needs to kill to eat, how did the alien suddenly appear full-size without any nourishment?
Correction: In the script, the Alien was caught eating all the crew's food that it could find in one of the food lockers, so it does indeed eat. One of the crew shot their flamethrower into the locker and the Alien then broke through a vent and into the air ducts. Also, the time between Kane dying and Brett dying was at least several hours. In the cuts scenes you see them first searching for the small Alien directly after it emerged from Kane. They then had to put Kane's body in it's shroud; clean up the awful mess in the dining room' perform the funeral ceremony and finally make the cattle prods and motion-detector. All of that would take a fair amount of time. It's not like the Alien grew to full size in only 20 minutes.
Correction: There's one big false assumption there - that the creature kills to eat. The extended cut of the film shows that in at least two cases, members of the crew were taken alive to create new eggs, and in other cases, the bodies are left apparently uneaten. The aliens in the film series have always shown the ability to grow to full size extremely quickly; the mechanism is unknown but it doesn't involve eating other lifeforms as no alien has ever been shown to attack before reaching full growth. The most likely explanation is that the additional mass required is simply taken from whatever the alien finds around it (metal, rock, whatever) and is incorporated into the body structure in some unexplained manner (possibly involving the breakdown of such matter via the acidic blood and its reconstitution in a form that the alien can make use of by some organ within the alien body).
Corrected entry: Several scenes on the story boards and in the script did not make the final cut of the film. Some weren't even filmed at all. Some of these scenes included a sexual encounter between Dallas and Ripley, who have their moment spoiled in horror when Kane's corpse, which they ejected hours before, drifts in front of their view and bangs into the window. The other more controversial scene that was not even filmed, but only hinted at, was a 'rape' scene involving Lambert and the Alien. The Alien sliding its tail between Lambert's legs was originally intended to be the start of a bizarre sodomy/rape sequence, but director Ridley Scott thought better of it and decided not to film that scene. The only inclination of the alien sodomizing or raping Lambert left in the film is the fact that her corpse, which we only get a brief glimpse of hanging from the ceiling, is stark naked.
Correction: When Lambert was killed by the Alien you heard her on the intercom and the sounds she was making certainly sounded like she was being raped.
Corrected entry: On the special edition: go to the main menu, highlight special features, press right, and you will get the dossiers for the crew.
Correction: This description vaguely resembles an easter egg from the "Alien Legacy" collection or "20th Anniversary Edition" but the wording for just about everything is a bit off.
Continuity mistake: When the ground crew prepares to leave, the captain tells them to take weapons. All three crewman are in suits with side arms on hips. These weapons are never seen the rest of the movie.
Suggested correction: With reference to the side arms mistake the weapons are seen, when Kane goes to look inside the egg before he is attacked he is carrying his side arm and holding it ready.
Corrected entry: The director's cut of the movie contains a continuity gap with James Cameron's Aliens. In the sequel, we learn that the eggs containing the facehuggers are laid by an Alien Queen, who is protected by drones and warriors. However, in the director's cut version of Alien, we see that the captured Brett and Dallas being slowly transformed into eggs when Ripley comes upon them as she races for the shuttle. (Even in the theatrical version of Alien, we don't actually see either Brett or Dallas being killed; we just assume they have been when the Alien grabs them.) When asked about this later, James Cameron replied that since the released film version of Alien omitted these scenes, he did not consider them canon and did not feel bound by them.
Correction: This can actually work in either the theatrical version or the director's cut. It's possible that the drones, not being capable of laying eggs themselves, can somehow change a living creature into an egg when faced with a situation where a queen is not around (the first egg created would become a queen, most likely). This would help the propagation of a species with such limited capabilities for growth. Kind of like some frogs have spontaneously changed gender when in a situation where there was a disproportionate number of one gender over the other.
Correction: The single Alien being able to create an egg from a human would also explain how the Queen in Aliens even got there.
Corrected entry: At the premiere of Alien, religious zealots set fire to the model of the alien, believing it to be the work of the devil.
Correction: Myth. While this verbatim description of the vandalism that destroyed Giger's model is still bouncing around the Internet, blaming "religious zealots, " there is apparently no documented factual evidence to substantiate it. In fact, the only source for the "religious zealot" claim comes from David A. McIntee's 2005 book "Beautiful Monsters: The Unofficial and Unauthorized Guide to the Alien and Predator Films, " which has been criticized for too much opinion, bias and speculation, and too little documented fact. In actual documented accounts, the arson of Giger's models at the Egyptian Theatre is blamed simply on "vandals, " with no mention of motivation, religious or otherwise.
Continuity mistake: Near the start, when Dallas is at the entrance to Mother, one of the lights to his left, the fifth one down from the ceiling, is not lit. The next shot from inside Mother looking out shows that light is now lit. This exact same thing happens a second time when Ripley is entering mother later in the movie. These two scenes must have been shot at the same time. (00:08:20 - 01:18:35)
Suggested correction: That light totally had enough time to light between the frames, because it was hidden by the sliding door for a brief moment. Lights were lit one at the time, not all at once, so this one starts to shine just a little bit later than all the others, that's it.
I consider this a valid mistake and the correction is a stretch. The lights only took about 2 seconds to light up, but she's at the door for almost 3.5 seconds after they're on and the last light did nothing. Then in the half second it took the door to open, the last light is now on.
Corrected entry: The escape shuttle used by Ripley and the cat is buffeted by a shock wave from the Nostromo's explosion, a shock wave that can't exist. In space, there is no medium through which a shock wave can propagate.
Correction: It's not a shockwave. She's just blown up a colossal ship behind her - what she's hit by is the vaporised remains of the ship, rushing outwards from the point of explosion.
You don't see or hear the remains of the refinery hitting the life craft AT ALL so this is an implausible explanation. AND the camera shows the refinery intact as the life craft is pulling away from it...where has the debris come from?
Correction: If sound can travel in space, shock waves can, too. This is standard skiffy film convention. It is not reality.
Correction: The oxygen supply had been turned back on because they were about to wake from hypersleep.