Continuity: When Magneto lands the Golden Gate Bridge on the island, as it hits land it is still very light. When the Brotherhood start to walk toward the island, it cuts to a wide shot of them still walking on the bridge, and it's suddenly dark.

Factual error: Take a look at Google Earth - the section of the Golden Gate Bridge Magneto breaks off (tower to tower, with a bit of overhang, 0.9 miles at most, more like 0.85) is not long enough to reach Alcatraz - the two closest points are 0.96 miles apart, and that's the very end of a pier, which most likely couldn't support the weight of the bridge anyway.

Continuity: In a scene where Logan pulls out the two horns from his stomach, the camera shows two holes on the singlet as part as his wounds. In the following scenes, the holes of the t-shirt have recovered (I know Logan has healing ability, but not his clothes).

Revealing: In the scene in the laboratory under the mansion, when Wolverine confronts Jean about Cyclops, there is a close up shot of Wolverine's hand holding Cyclops' glasses. In this shot there is a small cut visible on Wolverine's hand - his healing power should not allow this.

Continuity: As the scene where Angel is about to get the "cure" in the San Francisco skyscraper, you can see the reflection of San Francisco in the outside of the building - a huge hill with lots of buildings, and a large white tower at the very top. But when the camera switches to inside the building, looking outside, the view has suddenly changed to a view of the bay, and Alcatraz.

Continuity: In the scene where Magneto and Charles Xavier are in Jean Grey's house (when she is older and making everything around her float in the air), watch the book shelf when it falls down. At least 25 books fall out of the top shelf and in the next few shots you see that the number of books fallen has minimized greatly.

Continuity: When Storm confronts Wolverine when he's leaving, his position changes between shots. From over her shoulder, he's much closer then when the shot is over his shoulder.

Continuity: In the scene where Angel is about to be given the cure, there is a change in the hypodermic syringe used to administer the drug. As the camera shot switches between views of Angel being strapped in and Dr. Rao preparing the injection, the first view shows the hypodermic needle cover already having been removed. The camera switches to Angel then back. Dr. Rao, having completed the preparation for the injection, proceeds to remove the cover which had already been removed in the first shot.

Continuity: After Magneto declares war, troops are briefly seen exiting from a bus with brown boots. As they line up, you can see the boots have been replaced with black rubber ones.

Other: At the beginning of the credits, (of the version shown in cinemas) they have mis- spelled 'Starring', they put 'Strarring'

Continuity: Near the beginning when the boy is cutting his wings, his hand is reaching behind his back. During different shots he's reaching behind him with different hands.

Continuity: When Wolverine approaches Xavier's grave, the shadow of his head falls onto the grave. Then, after Jean has stopped telepathically speaking to him, the shadow of his head is left of the grave, even though Wolverine is in the same position. There was not enough time for his shadow to have moved that much.

Continuity: In the scene on Alcatraz, Collosus throws Wolverine at Magneto. After Wolverine is dragged along the floor and Magneto says something to him, Wolverine looks up at Magneto from the wrong direction (this is explained when you look at the deleted scenes but doesnt fit in the final cut).

Continuity: When Magneto is moving the cars on the bridge at the end, a reddish van in the center of the road is moved to the side. A couple of shots later, the same van is again moved from the center to the side.

Revealing: When Magneto is holding Wolverine up in the air in the forest you can plainly see one of the wires used to hold him up.

Factual error: After the troops are mobilized to fight against the Brotherhood and guard the cure clinics, they make a big show of them turning in their M16s and other metallic items and getting their plastic weapons so Magneto can't use the metal against them. But they wouldn't have had their M16s to begin with; you pick up your weapon after you arrive for mobilization at your unit. They would have showed up unarmed and then had the plastic weapons issued to them right after they reported for duty. (Most likely the scene was made just to get the point across to the audience that they need to get rid of all metal and to look flashy). Prior to the President responding to Magneto's declaration of war by mobilizing the troops, the cure clinics were guarded by civilian law enforcement; not US troops.

Revealing: In one shot during the scene where Bobby and Kitty are skating on the frozen fountain, Bobby's skates can be seen to be metal covered in ice, rather than the solid ice we saw when he made them.

Factual error: When Magneto has moved the Golden Gate Bridge, we see the President looking at a Satellite Image of Magneto's work. In this image, Alcatraz Island is bigger and closer to the shore than it is in real life.

Plot hole: When Magneto lands the bridge between LA and Alkatraz, only the ends of the bridge are on land, with the rest still suspended in the air despite having nothing to keep it there. Magneto could arguably be using his powers to keep it supported, but after he loses his powers it still doesn't collapse.

Continuity: After Beast hits Magneto with the four needles, they change place.