Other mistake: Towards the end of the movie, when Superman drops Gus off at the coal mine, Gus begins talking with the coal miners about him and Superman. He then rips open his shirt (as if he had a Superman costume on underneath). How did Gus know that Clark Kent tore his shirt like that in order to change into Superman, or keeps his suit under his clothes at all? The only people who know this fact are the ones who have seen the transformation from Clark to Superman, i.e. the audience.
Other mistake: The movies show that Superman can talk and live in space as normally as on earth, with no extra effort needed. Therefore, the scene of Superman choking and suffering inside a shield/ bubble with no air is totally senseless. The Krypotnite laser which does choke him appears after he has destroyed the bubble.