Continuity mistake: When Agents Mackelway and Charelton are driving to the scene where there is a murder victim in a car hanging at the edge of a cliff, we can see the dust trail from the car begin about 50 yards up the dirt road. With as little wind as there was in this scene, we should be able to see dust all the way up the road. Also, when they start talking with the local sheriff there is a very noticeable cloud of dust behind them, there is a brief cut away, then the dust cloud is totally gone.
Continuity mistake: When Howl first flies with Young Sophie, he wears a ring on each hand. As they take off, one of the rings momentarily vanishes.
Continuity mistake: Simon gets groceries, carries them home in two bags, and is then in the hallway without any groceries. It is never clear that he sets them down. (01:20:35 - 01:21:40)
Continuity mistake: When Crichton talks to Harvey (Scorpius in his head) about the Wormhole Weapon engineering project, one of the women in the scene leans on the hood of the car, with her glasses in her hand, chewing on the left arm of the glasses (the right arm is folded). The camera angle changes, and the arms are switched. The camera angle changes back, and the arms are switched back. (01:43:50)
Continuity mistake: Right at the end, as Alex and Luke are about to have sex, Alex takes her hair out of her ponytail style and lets it hang down loosely. Her hair is extremely 'poofy' at this time, sort of messy as well. The camera angle changes to Luke for two seconds, then back to Alex. Suddenly, her hair is combed down and straight now...with no 'poofyness' and no hair out of place.