Corrected entry: In the big fight scene at the end of the movie against The Brotherhood, Storm fights Callisto (Speed/mutant-detector) and kills her via electricity which comes out of her hands. Since Storm's power is to control weather, and weather control and electric shock are two very different things, she shouldn't be able to do this (in the first movie she had to summon lightning down from the sky to use against Toad).
Corrected entry: In the scene where Juggernaut is attempting to catch Kitty Pride and Leech, he runs and ends up hitting his head on the wall and knocking himself unconscious (due to the fact that Leech has the ability to nullify other mutants' powers). However, Juggernaut is not actually a mutant, as his power is derived from the suit he wears (an alien suit). Therefore, in reality he would have still bashed through the wall and Leech's power would have had no effect on him at all.kordhendry
Corrected entry: In the scene where Jean and Magneto are overlooking the camp of mutants, Magneto talks to Jean about her powers. He holds up the weapon with the antidote and says he can only control metal then levitates the weapon. The weapon was supposed to be made of plastic as revealed later in the movie. The alternate scene shows him levitating a metal mug instead which made sense with his line.
Corrected entry: When Shadowkat meets Leech in the complex, she can't phase through the wall to escape because being near Leech negates her mutant powers. When Juggernaut enters the same room, he is unable to break through the wall for the same reason, however Juggernaut technically isn't a mutant, his abilities were received through mysticism so his powers shouldn't have been affected.
Corrected entry: In the scene where Rogue talks to Wolverine about going to get the cure, she reveals that her real name is Marie. In the first X-men film, Rogue introduces herself to Wolverine as Marie after he reveals that his real name is Logan therefore eliminating the need for her to reveal her name in the third film.
Corrected entry: Juggernaut's power is the ability to gain great strength but only by building momentum. This was proved when the loss of momentum, by locking his arms and legs down in the mobile prison, is how they were able to contain him. However, when Kitty Pryde sinks him in the floor, he bursts out effortlessly, despite having his arms and legs fully pinned down in concrete and unable to gain momentum.
Corrected entry: When we see Magneto move the Golden Gate Bridge to Alcatraz he sets it down so that there is a bridge across the mainland to Alcatraz. The bridge is supported only by the island and the mainland, this wouldn't happen as a bridge that long and heavy would just collapse in the middle, that is why suspension bridges with supports in the middle are needed.