Continuity mistake: At the nut factory, when Mr. Salt is there with the ladies, and he is walking up to the podium, the microphone is facing towards where he is walking from. Then in the next shot when he is at the podium facing the ladies, the mic changes direction and is centered, facing him.
Continuity mistake: When Veruca is choosing a squirrel, she heads for the last one in line, furthest from the ladder. Then after it cuts away and back, she is headed towards the middle of the line, but then she is headed for the last one again. When the squirrels jump her, she is about 1/4 of the way down the line, starting from the ladder.
Continuity mistake: When the factory gates open for the contest winners, the shadows in the courtyard change between shots. [This is a reference to the first film in which the shadows shift a lot. It is also shown in other parodies of the original film, eg, the Family guy episode "Wasted talent". Still a valid mistake.]
Continuity mistake: The tire track of the rightmost truck (in the top-down shot) is completely wrong. All 5 of the trucks were parked parallel. Besides, we can see only one pair of tire tracks per truck, but when a truck turns, the path the front wheels move on has a larger radius than the one the back ones move on thus creating two tracks. All this was OK just a shot before.