Factual error: In any explosion the shock-wave will travel ahead of any debris thrown by the shock-wave. During the attack scenes there are numerous cases of debris, particularly vehicles, travelling and landing in still air ahead of the arrival of the shock-wave.
Continuity mistake: David calls Connie at the White House and she walks toward the divided pane windows, then pulls the curtain to the side. In the exterior shots facing her the pane's white grille is between her hand and face, but in the next interior shot looking out, there is only clear glass, though we should see the grille just as we see both sides of the curtain with her hand holding the right side. (00:38:25)
Visible crew/equipment: At the Area 51 lab, when President Whitmore is down on the ground in pain, in the shot from inside the lab facing the lab's outer hall, the alien costume only reaches just above the crewmember's waist - the costume straps attached to his pants are visible, as well as his arm. (Only visible on fullscreen DVD.)
Factual error: When the alien ship over New York blows up the Empire State Building you see the blastwave spill out in the street in front of the Empire State Building. This is in that part of the city that's built in a grid pattern. In front of the Empire State Building there's just another building, not a street where the blastwave and debris can spill into. All the people who are way down the street, looking at the building being hit by the beam just can't be there. (00:47:00)
Audio problem: When the Knights deploy their missiles with no results, we see in close-ups as they respond that Steven is Knight 1, Jimmy is Knight 7, and another Marine is Knight 3. After Steven says, "Knight 1. Sweet Luck. Echo, Fox 2," we see a close-up of Knight 3 and hear his voice (not Jimmy's) say, "Knight 7, Fox 2", though he is in fact Knight 3, and Jimmy is Knight 7. (01:00:45)
Continuity mistake: When David is getting drunk and he's talking to Connie, at one point he slams the bottle down on the counter and a little liquor sprays up out the opening. Then they talk for a second, and he picks the bottle back up to pour himself more, but he now needs to unscrew the cap which was just lying next to the bottle. (01:25:45)
Factual error: The US Bank Tower's placement in between Citi Group and Melon Bank is inconsistent from its real life position. Citi Group should be roughly directly parallel, not off-center at an angle.
Other mistake: When they're shooting the nuclear-bomb at the space craft for the first time (when it fails due to the shield on the alien space craft), you see that the airplane shooting the missile is breaking off to the left just after it's fired the missile. On the radar a few seconds later you see the airplane breaking off to the right. As if the radar displayed a mirrored view.
Factual error: When the aliens attack Novosibirsk, Russia, a map of "Russia" in Russian letters is displayed on-screen from what is supposed to be a Russian news broadcast. In fact, it's a map of the Soviet Union, St. Petersburg is incorrectly labeled as "Petrograd," Moscow is too far east, and Novosibirsk is very badly misspelled. (00:15:20)
Continuity mistake: When Captain Hiller is dragging the unconscious alien across the desert, the sky alternates between overcast and perfectly sunny depending on if it's a close up or far off view of Hiller. (01:07:30)
Factual error: In the opening scene, the plaque from the Apollo 11 landing is shown sitting in the lunar soil. The actual plaque is mounted to the landing module, right under the ladder. (00:01:00)
Continuity mistake: The scene after Jasmine's club pole dance, she is with her girlfriend in the dressing room. She is warning her girlfriend not to go to the alien rooftop site. Jasmine walks away undressed, but comes out a moment later with her shirt and pants on, and though she put her clothes on over her dance outfit it is still too quick to accomplish in that brief moment. (00:36:25)
Visible crew/equipment: When President Whitmore, General Grey and the rest return to the containment lab to see the live alien, Major Mitchell stands directly in front of the smoke filled lab and the camera equipment/crew are visible in the reflection on the glass. President Whitmore, General Grey and a few others are supposed to be the only ones in front of the three aliens' liquid chambers. (Only visible on fullscreen DVD.)
Continuity mistake: When Captain Hiller is in his dress uniform in the house and then outside beside the car, before he heads back to El Toro, the epaulette on his shoulder is out above the collar, in the next shot it is under the collar (where it belongs), but in the very next shot, it is out again. (00:29:35)