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: 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)
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 Domino is playing pool, in the wide shot, she is shown at the one of the corner pocket sides of the table, with Toad perched on the left corner pocket across from her. When the shot changes to her getting ready to take her shot, she is now standing on one of the side pocket sides of the table, with Toad similarly perched on the corner pocket on the left across from her, only now it would be on the same end of the table where she was originally standing. (00:21:57)
Continuity mistake: When Angel says "Thank you, I appreciate it," he is shown lowering his phone to just below his neck area. When the shot changes, the phone is already down by his waist. (00:21:36)