Continuity: When the fake Donovan is trying to rescue Julie, he is shot from behind. But in the next shot, the scorch mark is on his chest.

Revealing: After the failed raid on the Resistance's headquarters, Brian shoots the counterfeiter who led them there, but no scorch mark appears on his victim's shirt (later victims have these scorch marks).

Revealing: When Julie is almost converted, a fake Donovan bursts in and starts firing a blaster rifle. Look closely at the first shot: the rifle is held way too high, so the shot should have gone into the ceiling; yet the blast goes straight forward.

Plot hole: During the raid on the pumping station, Elias overpowers a Visitor guard and throws him off the catwalk - into a hall full of workers, engineers, and even more guards. Strange that no one notices.