Audio problem: In the "Candyman" song near the beginning of the movie, the candy store owner is on a ladder, about to drop candy into the kids' hands. When we see the kids holding up their hands and saying, "Me. Me.", none of their mouths are actually saying anything. (00:04:00)
Revealing mistake: Just before Charlie opens his winning Wonka bar, we see printed on the back label: "Packed by The Quaker Oats Company Chicago, Illinois". It is made clear in the film that no other companies are involved in the creation of Wonka's products - they're dispatched from his factory wrapped and ready to sell. (00:34:00)
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)
Revealing mistake: When Violet turns blue, in any shot facing her back you can see the blue light source used at the very left of the frame (widescreen only). (01:12:24)
Revealing mistake: You can clearly see the string holding the elevator as it flies over the city. (01:33:00)
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.
Revealing mistake: When Charlie and Grandpa Joe drink the fizzy lifting drink and are floating in the air you can see the hook that is connected to the wire that Charlie is being held up by.
Revealing mistake: When Violet turns into the blueberry you can see the reflection of the blue light in her hair. But in the same scenes where blue make-up is used instead of the light, you can see the regular flesh-tone under her hair and in her parting.
Revealing mistake: After Violet has chewed the gum and is blowing up, if you look near the bottom of her right leg, you can see the air hose that is blowing her up. Visible on full screen only.
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.
Revealing mistake: In the Egg Room, when the golden eggs are falling down onto the scale, and particularly when the egg Oompa lifts one onto the cart, you can see the lining on their sides, even though they are supposed to be actual goose eggs.
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.
Revealing mistake: In the scene where Charlie and his grandfather are floating from the fizzy lifting drinks, you can see the black harness Charlie is wearing.
Revealing mistake: In the scene where Willy Wonka and the group of golden ticket holders enter the room with the chocolate river, Willy Wonka picks up a mushroom head with his cane. If you look closely, you can see holes under the mushroom head where he has previously done this, probably more than one take for that scene.
Audio problem: During Veruca's song her lips don't match what she's saying.
Chosen answer: He felt that it took too many liberties with the story. In the original agreement, Dahl himself was to write the screenplay (he was, by that point, a not-unsuccessful screenwriter), only to find that his version of the script was subsequently heavily re-written, including what Dahl felt were a number of unnecessary gimmicks, such as Wonka's penchant for literary quotations. Even the title of the film was changed from the original "Charlie and the Chocolate Factory", in order to tie into the launch of the "Wonka Bar", a new candy bar made by the Quaker Oats company, who co-financed the film. Annoyed at all the changes, he ultimately disowned the film and refused to sell the cinematic rights to the sequel, "Charlie and the Great Glass Elevator".
Tailkinker ★