Continuity mistake: When Willy Wonka first opens the door to the chocolate room for his guests, the long, shrinking corridor they've all just walked down is no longer behind them. Instead, there's now a short patio with a huge wrought-iron gate. (00:54:20)
Continuity mistake: When Wonka hugs Charlie saying he won, Wonka's hair at his left is unruly. When he invites "Slugworth" in, his hair is back in (better) shape. (01:35:05)
Continuity mistake: When Wonka is leading the group down the stairs into his factory, Veruca's right arm changes position from her hand on the bannister to her entire forearm resting on it.
Continuity mistake: A tree suddenly appears behind Grandpa Joe, Charlie, and the Beauregard's that wasn't there before, as they rise to see Wonka emerge from his factory.
Continuity mistake: When Mr. Wonka is first walking toward the crowd, his walk is much longer than the actual path. Watch the shadows change on the overhead shots as the day of filming went by.
Continuity mistake: When they're in the room with Wonkavision, as Mike Teevee jumps up on the platform to get shrunk, in the background an Oompa Loompa puts goggles on, then in the very next shot he puts them on again, with no time to have taken them back off.
Continuity mistake: When Willy Wonka presses the button for the Spectacular Gum Making Machine, all of its gears and parts and contraptions start working. In one shot, a tray of a pale white chunky substance is covered by a lid. As the lid lifts off of the tray, the pale white chunks are now bright colors. You can see where the cut in the shot was made for them to replace the first tray with the second tray. There is a slight jump in the position of the lid and the misty fog in the shot changes in the same instant.
Continuity mistake: If you look closely at several scenes, Veruca Salt's and Violet Beauregard's hairstyles change. For example, Violet's hair is wavy, then it is even curlier.
Continuity mistake: When Grandpa Joe gives Charlie the candy bar bought with the tobacco money, Joe pulls it out, holding it at the top right and bottom left corners. When the shot cuts to Charlie and he says "Grandpa, that money was for tobacco." you see Grandpa Joe in the foreground of the shot, and his right hand has moved from the top right corner to the lower half of the candy bar. When the shot cuts back, his hands are as they were before, on the top right and bottom left corners of the candy bar.
Continuity mistake: When Wonka's boat is about to depart, two shots are cut together, but the sound recorded of the second is used over both. This results in a clear view of the Oompa Loompa steering the boat with the boat's bell (and the rope to ring it) not being rung by anyone whilst you can hear it ringing - then the shot suddenly changes, and the Oompa Loompa is obviously ringing it in time to the sound.
Continuity mistake: On the boat ride, when Wonka explains about "The Sailor's Way", his head changes position between shots.
Continuity mistake: After introducing Mr. Wilkerson, Wonka's hands magically appear on Charlie's shoulders.
Continuity mistake: When Veruca tells her dad that she wants a golden goose the stuff in the bowls behind them keeps changing.
Continuity mistake: At the Everlasting Gobstopper machine, Veruca Salt arrives before her father, and when Wonka announces the name of the candy, she and her father turn to each other and exchange glances. However, the next shot shows Veruca's dad just arriving at the machine and joining her.
Continuity mistake: In the contract signing scene, Violet and her father are close to Wonka's right elbow, but when the shot changes to Veruca and her father's view, they are further away, then close to Wonka again in a later shot.
Continuity mistake: When Grandpa Joe, Charlie, and Willy Wonka get into the Wonkavator for the first time from Wonka's office, the Wonkavator has a plain hexagonal shape. As it flies over the city, however, it sports an elaborate design complete with an ornate minaret on top.
Continuity mistake: In the scene where Wonka shows the tour the Everlasting Gobstopper machine, you can see that the candy is already on the finished belt before he turns it on. In the close up of the candy, there are a lot of extra candy, but after they get passed out, the excess is gone.
Continuity mistake: When Wonka introduces the geese that lay the golden eggs, the geese change positions between shots.
Continuity mistake: When they are all in the inventing room, and Mike TeeVee is eating the explosive candy, you can see the explosion come out of the machine he is standing next to. In the next scene, when Mrs. TeeVee is leaning over him, he blows out a puff of smoke like it had come from his mouth.
Continuity mistake: When Violet is introducing herself to Willy Wonka, her purse strap is resting beneath her collar. When Mr. Beuregarde pushes her away to introduce himself, the strap has moved above her collar.
Chosen answer: In the original book, Charlie has an obsession with chocolate that he only satiates once a year on his birthday. Also, at this point in the book, the Bucket family is going through an extremely hard time and Charlie has had less food than he usually would have, so he is EXTREMELY hungry.