Revealing: In the Special Edition of the film, in the scene where the Marines are conducting their initial search of the colony, the shot where Hudson and Vasquez enter the "negative situation" room (where they find the hamster) is obviously sped up. You can tell by how quickly Vasquez seems to move when she comes through the door.

Revealing: Briefly after landing on the planet, we see the APC trundle across the ground. The way it moves shows it is a model, every little bump makes it jump up and down. This is a shame, considering that when it is inside the facility and in subsequent shots, it looks very good.

Revealing: In the scene where Ripley rescues Newt, there comes an alien from a corner and it jumps from side to side. In the second jump, you can see two wires on its back.

Continuity: In the shot were Ripley is driving the crew away from the aliens, note the big dent in the vehicle. Then in another shot when they finally get outside, there's a shot from the side and the dent is gone.

Continuity: In the battle scene between Ripley (in the loader) and the Queen, the caution light and cover are damaged as the Queen tries to pull the loader into the airlock when Ripley tries to drop it. In the next scene, we see the loader lying on the floor of the airlock with the yellow cover still in one piece.

Visible crew/equipment: In the scene where Newt and Ripley are trapped in a room with two facehuggers, Newt traps one with a table, and you can briefly see the operator's hand manipulating the legs.

Continuity: In the original "Alien", Ripley dons a space suit in the shuttle, in preparation to decompressing the quarters to the hard vacuum of space. The helmet has no light on its top. Subsequently, in "Aliens", the opening shots pan through the shuttle chamber, and Ripley's helmet sits there...with a light on its top.

Continuity: In the extended edition of the film, Ripley, Gorman, Burke, and Bishop meet up with Hicks at the entranceway. It is raining heavily and Ripley's hair gets soaked. But when she is inside a few minutes later, it looks as if she has had time to dry her hair thoroughly between now and then.

Continuity: When the marines first encounter the Alien hive in the reactor, and Ghorman asks Hudson what he's seeing, we're treated to a shot of Vasquez' helmet cam, and her name in the bottom right is missing her first initial. [Timecodes are from the special edition of the movie. The first one is the one for the error, and the second is a different scene with the initial present for comparison.]

Continuity: Towards the end of the film where Ripley and Bishop are in the dropship flying towards the atmosphere processors, Ripley begins to build a composite weapon from a flamethrower and a pulse rifle. She pulls a flamethrower from a rack on the wall, but lays pulse rifle on the deck of the ship, and then pulls a pulse rifle from the rack and lays a flamethrower on top of the pulse rifle.

Continuity: Right after Ripley is rescued from the Narcissus, look at her hair in the clinic. At first there is a wide angle shot of the nurse coming over to her with some small talk. Then, when the shot changes to a close up of Ripley and the nurse, her hair has puffed out about 2 inches more.

Other: there are 2 squads of marines in the film...9 in total. Squad one is Apone, Vasquez, Hudson, Crowe, Wierzbowski. Squad 2 is Hicks, Frost, Dietrich, Drake. But as the marines enter the compound you clearly see 5 marines running up to the door, and shortly after, Apone shouts for second squad to move up. As they move look closely and you will see 5 more moving up. 5+5=10, who is the mystery marine?

Revealing: When Bishop is doing his knife trick on Hudson it's obviously fast forwarded as you can clearly see the head of Apone in the background move way too fast for real life. No one can move their head that fast without snapping their neck.

Continuity: Pulse rifles have 10 mm caseless ammo, but if you watch the scene where Vasquez depletes her rifle and then switches to the pistol, there clearly are shell cases being spat out.

Audio problem: In the beginning of the scene where the soldiers are eating in the mess hall, the soundtrack of background noise is played, then repeated.

Continuity: In the scene where the drop ship is about to leave the main ship look at the picture on the side of the ship, just to the left of the parrots window. There is a symbol of an eagle. Note which way it is facing. Later when the ship is on the planets surface and the marines are leaving it, the eagle is facing the other way.

Continuity: When Ripley is giving Newt the cup of hot Chocolate the handle is on Newt's right. When it shows the close up shots the handle is on Newt's left.

Continuity: When Gorman and Burke come to see Ripley to persuade her to come to LV-426, Burke hands her a plastic card so she can call him if she changes her mind. At this point Ripley lights a cigarette. The scene then cuts to a view of the whole room, and Ripley can be seen lighting the cigarette again.

Revealing: When Michael Biehn's character reaches for Newt for the first time while she's cowering in the recess of the hallway, he cries out just before she bites him.

Continuity: When Ripley enters the hive, right before she lights the second flare, she fires a flamethrower burst. When she does, the starter flame goes out, then in the next scene it is on again.