Continuity mistake: The position of Cable's gun when it is holstered on his back varies throughout the episode. Sometimes it is slanted at a 45° angle with the butt going over his right shoulder, sometimes it is sticking straight up with the butt going over his left shoulder, etc.
Add timeSerious B
Continuity mistake: When Mystique first impersonates Shard in order to fool Psylocke, both Mystique and the real Shard are missing the gun holster that is usually on top of Shard's right shoulder. When Pyslocke and Wolverine both state that they can see through Mystique's deception, the gun holster has suddenly appeared on Mystique's right shoulder.
Continuity mistake: The length of the chain attached to the collar of Archangel's guard dog varies. When the dog is first shown, the chain is only shown to be around three feet long. When the dog discovers Psylocke, it is able to run several feet towards her and away from the wall where it was chained up.
Plot hole: Beast comments on Mr. Sinister's new-found time travel abilities. However, Beast has no way of knowing that Mr. Sinister is time traveling. He only knows that Mr. Sinister is using portals, which could just as well be for teleportation.