Continuity mistake: When Mugsy takes Bugs into the other room, you can see the door has no handle, but when Rocky draws a gun and goes to see Bugs, a handle appears from nowhere.
Continuity mistake: When Piggy is seated at the dinner table, there is a bowl of fruit with a yellow lid next to it, and Piggy has in front of him a plate with a spoon on one side and a knife and fork on the other. After Piggy's mother stops him from taking some fruit, we cut back to Piggy, and the bowl of fruit and yellow lid have disappeared, and he only now has a spoon by the plate.
Plot hole: Helena is ordered to fly or be thrown off the tower, bearing the brunt for Simon's failure. But the flying apparatus is still up there, and so is her servant who was going to secretly operate it so that Simon could pretend to fly around. All she needs is right there in front of her. She's supposed to be cunning and resourceful, and she could have saved her life simply by following the original plan.
Continuity mistake: The two workers are being dismissed by their boss after their 'too zealant' repairs of the streetcar. Shot from behind when he stops them as they walk away, you can see him place his right hand flat on the desk, directly on the wood. Next shot and his hand is in a different position and on the papers. (00:05:30)
Revealing mistake: Many of the cavalry soldiers were carrying M-1 Garand rifles (WW2 era rifles).
Continuity mistake: When Frisky Puppy is looking inside the box at the dump, the fence behind him is grey, but in the next shot it is white.
Continuity mistake: When Tom rushes up with his knife, fork and dish to get his dinner from the cook, you can see that Tom's knife is pointing straight but in the next shot it is now pointing to the right.