Continuity mistake: The birth of the Predalien in this movie is completely different than it was in the first AVP. The lights on the table are different and the Predalien bursts out differently than in the first film. (00:01:30)
Continuity mistake: When the guy with the predator gun shoots the gate at the end, so they go to the chopper, the wire fence keeps changing its shape in different shots. (01:24:25)
Continuity mistake: Near the end of the film, before the helicopter lifts off, Kelly kills an alien by shooting through the front window. Later, when the helicopter is in flight and trying to escape the nuclear blast, the bullets holes are gone.
Continuity mistake: When the last guy dies as he tries to escape out the swimming pool window, a large amount of blood lands on the window. The shot cuts to Ricky looking worried, then the next shot shows Ricky leaving. In the background you can see that the blood on the window is now missing. (00:51:10)
Continuity mistake: The facehuggers detach from the hunter and child near the beginning of the film, but when the Predator scans them they are still attached.
Continuity mistake: When they go to collect weapons, Morales walks in the building door while Dallas steps in to the doorway. When it cuts, Dallas is gone and the doorway is clear. (01:00:45)
Continuity mistake: When Ricky gets in to his room through the window and is surprised by his brother, he has his shirt hanging over his shoulder. The pattern the shirt lies on his shoulder change between shots. (00:16:45)
Continuity mistake: When the predator goes to the crashed ship and finds his friend dead, he takes out the vial to analyze and track the aliens. When he takes the vial, it's empty: when he searches for liquids, it's half full, and it's again empty when he takes the sample. (00:22:55)
Answer: Given that Alien is set in 2122, I think it can be safely said that, no, it's not.
Tailkinker