Other mistake: In the scene where Ripley throws the basketball at Johner, Christie says to Ripley, "Ok, I've got a new game, tag .." He hits her with the handles straight in the face once, he misses the next shot, misses again, and Ripley hits him to the ground, but you neither see or hear the handles fall. (00:23:15)
Other mistake: Toward the beginning, when the characters wonder aloud what the rumbling noise is, someone suggests that it's the ventilation system, to which Rennes responds "No vents." However, in the passages between rooms there are panels with ventilation slits in them (which you can plainly see even as Rennes says the line), and it's pretty impossible that the characteristically level-headed and observant Rennes wouldn't have noticed that.
Other mistake: When they have the baby Rex and the parents approach for the infant, there's an outside shot of the T-Rex roaring as Ian moves away to the other side. After he does that the Rex on the other side silently roars, then that same roar bit is repeated from inside the trailer in the very next shot, but the roar is added in, showing repeated takes.
Other mistake: Towards the beginning when someone is looking at a newspaper about the airliner being blown up, there are nonsense articles on the paper and pictures of people that don't match the names under them. With some white guy's picture over the name Michael Jordan on the left of the page, and then on the right a picture of a white woman with the name Will Smith under it.Quantom X