Continuity mistake: When King Arthur is fighting the Black Knight, there is a fire behind the Black Knight that is lit in some shots and nearly out in others. (00:15:55)
Continuity mistake: Near the end, Sam Clayton is nearing the finish. The audio leads you to believe that the horse is breathing VERY hard, but when the camera shows the horse, the nostrils are NOT flared as they would be on a horse that has been run to exhaustion (or even down the block). Also, the people filming this scene obviously have no clue about the nature of sweating in horses. They showed "lather" all through the horse's mane. The ONLY places horses will lather while sweating is where something is rubbing, i.e. underneath the saddle, the bridle or breast collar, where the reins rub on the neck or between their back legs.
Continuity mistake: When the RV is driving to Amarillo towards the end of the film, the vehicle is coming towards a detour sign and we see a group of road workers, one of which is a bearded man with a cowboy hat and no t-shirt. But when we see a view from the RV going towards the detour sign, the bearded man is seen walking towards his colleagues.
Continuity mistake: When the children are getting ready to go to the movies and are waiting for the bus, Truck's fingers are in a cast from breaking/spraining his fingers during his fight with Tony. However after the movie, when they're getting back on the bus the cast is gone and his fingers are fine.
Continuity mistake: In the scene after the first real battle of two tribes, the winning chieftain is about to chop off the heads of his enemies and is stopped by Sean Connery and Michael Caine. The chief threatens to lop off the head of the Connery character and is hit across the hand with the arrow he is carrying. The arrow breaks and pieces can be seen to fly off. In the next shot of Sean Connery the arrow is back in one piece.
Continuity mistake: When Molly dismounts her horse near the end of the movie the blanket slides off. A second later the blanket appears back on the horse.