Plot hole: Diana manages to escape at the end by stealing a shuttlecraft. But how did she manage to get there, when most of the mothership (and certainly the landing bay) was contaminated with red dust?

Revealing: During the final battle in the mothership hangar, Donovan shoots a Visitor soldier who falls off his catwalk onto a transporter. When he impacts, a styrofoam block used to cushion his fall bounces off the roof.

Factual error: When the world celebrates the Visitors' flight, there are scenes of joyous people from all around the world. Curiously, in each of these scenes it is daytime - even in Italy, China, and India, where it would be either night or dawn, given that L.A. time of the attacks is between 11 and 12 AM.

Continuity: When the Red Dust is spread, there is a brief shot of some California citizens watching, and we see the Bernsteins among them. But the actress at George Mofogen/Mr. Bernstein's side is not Bonnie Bartlett, who played Mrs. Bernstein in the first two episodes.

Factual error: As the Visitors are evacuating the mother-ship's control room, we see outside and the view over Los Angeles is obscured by a thick red smog. There's no way the red dust would be concentrated like that, given the limited quantities that were dispersed.