Other mistake: When Magma is running from the MRD at the beginning, her feet are so hot that she leaves magma-filled footprints in the ground, but somehow her shoes remain intact. (00:01:54 - 00:02:34)
Continuity mistake: When Wolverine knocks out the security guard, he collapses in front of the parking arm. When Gambit and Wolverine are shown looking up at the water tower, the parking arm is just behind them, and the guard is no longer there. (00:14:17 - 00:14:47)
Continuity mistake: When Wolverine is taking cover from the Sentinel Prowler, there is a blast mark in the pillar by his head. After Gambit asks Wolverine to give him back the collar, the blast mark has disappeared. (00:20:55)
Continuity mistake: When Wolverine returns home at the end, the counter where Forge is standing is across from the end of the table where Shadowcat and Iceman are sitting. In the final shot before the credits roll, Forge and the counter are now behind Shadowcat. (00:21:58)
Revealing mistake: When Cyclops asks Emma Frost what is happening when Shadow King is transferring his consciousness from Storm's mind into Wolverine's, you can see Cyclops and Emma have white outlines drawn around them, indicating they were drawn separately and composited into the shot. (00:19:06)
Continuity mistake: When Angel is saying goodbye to Wolverine, the driver's side door of his car is open, and he is standing on the interior side of it. When the shot changes, you can see the door is now closed (note the window glare). (00:03:41)
Continuity mistake: When Cyclops tries to shoot an optic blast at Shadow King's astral form, his right hand is bare. When Shadow King attempts to possess Cyclops, he is suddenly wearing a glove on his right hand. Both of his hands are then bare when he is helping Storm to her feet. (00:19:38)
Continuity mistake: When the X-Men are following Magneto to see Xavier, Cyclops is on the far left and Iceman is standing next to him. Once Magneto has opened a doorway to the room Xavier is in, Cyclops and Iceman have swapped places. (00:17:10)
Continuity mistake: When Magneto uses his powers to create a hole in the metal wall, the edges of the wall surrounding the hole are smooth. When the shot changes, the edges suddenly look crumpled. (00:17:16)
Continuity mistake: When Emma Frost is lamenting her students being taken away from her, she is standing inches away from the window. A couple of shots later, and she has instantly moved several feet away from the window. (00:04:44)
Continuity mistake: When Shadowcat tells Iceman that Emma Frost knows what he is thinking, the shocked expression on his face is drastically more pronounced when the shot changes. (00:05:37)
Continuity mistake: When Magneto is telling Wolverine that Xavier wouldn't approve of his commando raid, his neck area is flesh colored, when it was previously shown to be purple because of his costume. (00:16:45)
Continuity mistake: When Wolverine is scolding Cyclops in his hotel room, Cyclops is directly facing the wall in front of him, with Wolverine on his right. At one point Cyclops is suddenly sitting in line with the corner of the room, and Wolverine is now directly in front of him. (00:10:30)
Continuity mistake: After Cyclops blasts Wolverine out of his hotel room and Wolverine says "Good talk," the half of Wolverine's necklace with his dog tag that is supposed to be draped over his left side is missing. (00:10:55)
Continuity mistake: When Blob lifts up Angel, he does so by his right shoulder. When the shot changes, he is now holding him up by his left shoulder. (00:13:23)
Continuity mistake: When Wolverine enters the lab to talk to Beast, Beast is sitting in the chair on the middle-right. After he shows Wolverine that he searched for Kitty and Colossus, he is now sitting in the chair on the middle-left. (00:14:02)
Continuity mistake: After the POV shot of Domino's sniper scope pulls up, a billboard with Magneto on it is on the right side of the screen, over a building with a red roof. When the shot changes, Domino is perched at the bottom left of the same billboard. If she was perched there, then the billboard could not have been to her right when she raised the sniper scope. Additionally, the roof of the building is now white. It's not a separate billboard on a different building either, because the waterfront and docks are the same angle respective to the first shot of the billboard and the shot of Domino loading the magazine into the gun. (00:18:19 - 00:18:42)