Corrected entry: In Janie's houseboat, when Elizabeth keeps telling Fred not to touch any buttons, watch the parrot toy hanging on a perch. Between wideshots and close-ups there is a small fan hanging beside it which keeps disappearing / reappearing. (00:40:00)
Corrected entry: When Fred's imaginary friend's face is about to blow up, look at him closely and you will see that it is not the guy's face, it's made of Plasticine.
Correction: Obviously they use special effects, they are not going to actually blow up someone's head. If you have to look closely to see an effect it probably worked pretty well. If it's not blatantly fake looking with casual viewing, it can hardly be a mistake.
Correction: This is wrong. There's no mistake between these two shots. You're not paying attention to the camera angle change - the fan appears in both shots. The little fan is behind Lizzie's head, which you catch a glimpse of when she keeps repeating "yeah" to Fred. It just appears in front of the parrot when the camera angle changes.