Corrected entry: The king nor his army ever seem to see the huge beanstalk when they find Jack and never realise it until Jack points it out. The beanstalk was too big for them to miss. One should have at least noticed the beanstalk on their way over there.
Corrected entry: When General Fallon takes the crown as a ring, and Jack takes it, the size of the crown changes.
Correction: The ring / crown is supposed to change size to the bearer... It is magic.
Corrected entry: When Jack and the other humans make it up the bean stalk for the first time, they are shown above the cloud line. At that altitude, the air would be very thin, making it difficult for them to breathe. Yet the movie shows them having no issues with this whatsoever, even being very physically active.
Correction: By the same logic, the land of the giants shouldn't be floating due to gravity. It's a fantasy world. Things such as lack of air obviously do not apply here and maybe the magic of the beanstalk means there's enough air to breathe. Either way it's magic so we can't know what the scientific properties of a giant beanstalk and a floating giant kingdom are.
Corrected entry: The proportion/size of the giants changes through the whole film.
Correction: I realize this is an easy mistake claim. While watching the movie, the visual appearance and actions can make size comparisons difficult. However, as a supervisor in one of the digital effects companies involved in creating the CGI cast members in this motion picture, I can assure you great pains were taken to maintain consistent size and proportions to all of the CGI cast members. In fact, without exact measurements, the composition and collaboration between the several digital effect teams would have been impossible.
Correction: They did notice the bean stalk. That is why he is out with his army.