Continuity mistake: During the scene in the mall when the girl is in the dressing room, she keeps putting on more layers of clothing. But as they are shooting different shots she will have a hot pink shirt on, then it is back on the hanger, and then back on again. It switches back and forth many times. (01:00:50)
Continuity mistake: Opening scene - meteor smashing into the car and you see the windshield flying out. Next day, character is driving the car and viola the windshield is still intact. (00:03:46)
Continuity mistake: When Dan Akroyd is discussing the aliens with the military, the digital clock behind him reads different, non-consecutive, numbers each time they show it. (01:07:55)
Continuity mistake: When Ira and Jones break into the secured area to get the specimens, they lay down in front of the barbed wire. Ida is wearing a black Colonel Uniform and Jones is wearing a Private Uniform. But when they get inside the facility Ida's uniform is clean and has no dust marks. (00:34:01)
Continuity mistake: In the scene near the end when they first drive under the thing in the fire truck and it 'passes gas' on them, Orlando's glasses disappear during the 'passing' and then reappear a couple of shots later. (01:26:50)
Continuity mistake: During many scenes of the movie, you can notice that Orlando Jones has no glass in his glasses at times, then does at other points. When they are in court, he puts his fingers through the frame to rubs his eyes. [Some people have said they're meant to be fake in order to make him look clever, but they've definitely got glass in some scenes.] (00:32:31)
Continuity mistake: When Julienne Moore's character trips over, from the distant shot she gets up onto her hands and knees, then when her garter is seen, she is lying flat on the floor again.
Continuity mistake: When the guy on the green is waiting for his date, the champagne bottle mysteriously changes places. When setting the bottle down the lights from above change angles when he's walking to wash off the spillage. (00:45:20)
Continuity mistake: At the end of the film when David Duchovny and Orlando Jones go up the ladder to squirt the Head and Shoulders into 'the hole', Orlando Jones gets sucked up into the alien and when he is pulled out he is covered in slime from head to toe, (including his glasses), as is David Duchovny. However, in the next shot of them going down the ladder there is no slime on them at all. In the next shot when they are standing at the bottom, while the truck pulls away, neither of them have much slime on them, and Orlando Jones' glasses are completely clean. The amount of slime they are covered in changes throughout the next few shots. (01:32:50)
Continuity mistake: When all the students are partying outside the college, it shows the red Jeep parked up outside the college. In the next scene, it shows the "heroes" driving up to the college in the Jeep and getting out of it.