Continuity mistake: Near the beginning when the boy is waiting for the men to return and he has the bucket of water, you hear the water slosh but the scrawny boy runs so effortlessly with it and you never hear it slosh again. Then when he is at the fence with his back to them, you see the bottom of the bucket is wet, but there's no water in it. (00:09:30)
Continuity mistake: When the spy was trying to kill Wallace, he was seen swinging his sword forward. The shot cut to Stephen throwing his knife. When the shot cut back to the spy being hit by Stephen's knife, he was pulling back his sword to get ready for a forward swing. What? Did he miss on his first attempt and had to try again?
Factual error: The title of the Duke of York did not yet exist in the 13th century - it was instituted only later and was normally used only by a younger son of the King.
Continuity mistake: When Philip is thrown out the window by King Edward we see him flipping over in the air so that he will hit the ground on his back. But when the camera changes to the window view we see that Philip is lying on his front.
Factual error: In the movie the Scots sack the English city of York. Actually they sacked the city of Carlisle.
Continuity mistake: Watch the group of English soldiers that ride out to present the King's terms at Stirling. After Wallace insults them, they turn around and begin to leave. The sounds of their horses riding off are very audible. After Wallace's talk with the three nobles, their group breaks up and begins to ride back. A panoramic shot of the field is shown and the English representatives have just started to leave.
Continuity mistake: In the battle scene where they flanked their forces and and were going to use the long wooden spears on England's knights, they already had the spears out when it showed England's horses coming closer. Just look around them. It only shows for a second when it is zooming in pretty fast.
Continuity mistake: Near the end of the battle of Stirling (the first big one), an English officer on a horse comes at Wallace. Wallace swings his sword at the feet of the horse, knocking it and the officer down. As the officer falls his sword goes from one hand to the other several times.
Other mistake: After the fight at Falkirk where Robert The Bruce is walking through the field, there is a woman walking checking the bodies. All these people clearly are supposed to be dead. The woman lifts the head of a man and then puts it down. After she lets go of the head, the boy picks up his head and looks to his side.
Continuity mistake: In the scene where Wallace surrenders to the local magistrate, after Wallace has struck the English soldier that was holding the reigns of the horse, a second soldier attacks the horse with a spear. The spearhead is seen as the soldier starts the attack, after the cut the spearhead is gone, before it strikes the horse. The un-headed spear then hits the harness of the horse where it sticks as the horse rears, and the harness moves from the front of the horse's neck between the legs of the horse to the side, somehow passing through the raised legs of the horse. (00:49:20)
Revealing mistake: When his wife gets attacked, Wallace jumps over a roof and you can clearly see him wearing modern black briefs.
Continuity mistake: At the end of the movie the executioner bends down to bind William's feet. The scene shows the rope starting around his feet and then a second later William is yanked into the air with a complicated noose-like knot holding his lower body to the ground. How did they make that knot so fast?
Continuity mistake: When Wallace is saved by Steven, right after he meets him, watch Steven as he is about to throw the small sword. When he comes out of the brush and starts running, he gets past the two trees in front of him, then it cuts to Wallace aiming his bow at him, then it cuts back to Steven and he is back behind the trees.
Continuity mistake: At the wedding scene near the beginning of the film, Wallace challenges Hamish to throw a large rock at him. He throws the rock, and in slow motion the rock is clearly on Wallace's left side; he even leans a little to his right as the rock starts to pass by on his left. But in the next angle the rock is very clearly on his right. (00:21:10)
Continuity mistake: When Wallace pounds an English soldier with a large mallet, in the village where his wife was killed, watch the third hit. Wallace hits the soldier in the hip and then in the back. On the third hit, the mallet comes down at least an inch or two from the soldiers head, missing. The soldier jumps as if he was hit.
Factual error: Some more errors about Princess Isabella: at the height of William Wallace's rebellion Edward I sends her as an ambassador to negotiate with Wallace (and spy on the Scots) instead she falls in love with Wallace. Princess Isabella was born in 1292: Wallace's rebellion was at its height during 1297-8, so she could have been no more than 6 at the time. (Somebody else has already observed that she was only 13 at the time of Wallace's execution.) Isabella's first language would (obviously) have been French, a 13th century Scotsman would speak either a heavily accented Scottish version of English, or Scots Gaelic, but Isabella has no communication difficulties in Scotland. The Wallace-Isabella affair is also absurd, since it is implausible that, at the height of a war, an unaccompanied young woman, let alone a princess engaged to the heir to the throne of England, would be sent into the heart of a war zone as an envoy and a spy.
Continuity mistake: At Stirling when the Scottish attack on horse, there is a scene where an Englishman is being sliced by a sword and is quite bloody. Then it cuts to him being run over by two horses and you can see that it is not the same man nor are there any traces of blood on him. Then it cuts to him falling to the ground and he is again quite bloody. (01:26:50)