Right after the aliens land, Terry walks toward the window and his Superman tattoo is visible on his right upper arm. However, in a previous scene, when he is walking to the swimming pool bar, the tattoo does not exist.
Candice's hair changes from being loose when she lies down on the couch to being tied up when she wakes to the sound of the air strike.
When Terry pulls back the blinds and says "There's something down there," the camera cuts to a foggy street. One of the giant aliens is visible for about 2 seconds, but the aliens don't actually arrive until later in the movie.
Jarrod's hair changes lengths when walking down the hallway before meeting Walt.
The color of Elaine's pants change after Jarrod and Terry leave the apartment. Evidence of this is seen when Terry comes back from Walt's apartment.
Towards the end of the movie as the camera is showing the attacks on various other major cities some air conditioners are obviously moving (fans turning) although the power is supposed to be gone.
While Jarrod is taking photos on the rooftop, the camera has a sound of film advancing, but digital cameras don't have that feature.
A TV is shown with an Emergency Broadcast System alert. The EBS was replaced by the Emergency Alert System in 1997.