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)
Suggested correction: You answered your own correction, it isn't the same man.
Continuity mistake: When Wallace is a boy and they are at the grave to bury his father and brother, the shovels of dirt shake the wrapped dummy body in the grave.
Continuity mistake: When the princess and her chambermaid are talking about William and how they killed his wife, at the end of the conversation, the princess leans back against the edge of the archway. In the next shot from over her left shoulder, she's not leaning back, but sitting straight up.
Continuity mistake: After being knighted, William says that he will invade England. In the close-up shots of Robert in the group reacting to him saying this, you can see the man whose bride was taken away by the English lord earlier in the film behind him. But, in the wide shots, he's not there. It's just some random man behind him.
Audio problem: At the end, when the sword is thrown and sticks into the ground, the sound of the sword sticking into the ground is not synced up with the impact.
Character mistake: At the beginning, in the funeral of the young lady, the priest says in Latin the traditional "In nomine patris et filii et spiritus sancti", but he says the last word wrong, "sanctus" instead of "sancti."
Continuity mistake: During the battle of Stirling, the archers' arrows hit the Scottish shields and are sticking out. When the army stands up to mock the English again, the arrows are gone.
Continuity mistake: After Wallace kills the noble and his crew for killing his wife there's blood on his face. At the funeral there is no blood on his face. The night of the funeral the blood on his face returns.
Continuity mistake: When Mel Gibson is disembowelled, in one shot there's no blood on his neck, but in the very next shot there is.
Suggested correction: Could that be because in the first scene his shirt is torn open, and they haven't started the disembowelment. Then they start the process and blood spurts up across his chest and neck?
Continuity mistake: At Stirling when the English superior charges Wallace, as Wallace shouts "Bastard." you can't see any sunlight on Wallace. When it cuts the sun is shining quite well on him and on his surroundings. (01:27:35)
Continuity mistake: When the English and the Scots come together at the Battle of Stirling look at one of the Englishmen's swords: it is bloodied even though he has just engaged the enemy.
Continuity mistake: In the scene where Longshanks returns from France, confronts Prince Edward, and the soldier has left the basket with the head of the Prince of York, Edward reaches to remove the cover with his left hand, his right hand is on his hip. When the angle changes he is lifting the cover off with his right hand and his left is on his hip, when the angle cuts back, his right hand is back on his hip and his left hand is moving away from the basket. (01:41:30)
Continuity mistake: During the funeral for Wallace's father and brother, various people change positions. Murron starts out in front of her mother, frame left, then is in front of her father, frame right, then is back in front of her mother. Campbell and Hamish start out beside Wallace, jump to about 18 apart, then behind Wallace, then back to about 18 inches apart. (00:10:40)
Continuity mistake: When Wallace was in the bedchamber of a noble lord, he takes out a chain with a ball at the end. The chain is wrapped twice around his fist, and the ball is dangling under his fist; however, when Wallace swings the weapon, the chain is leading outwards from the top of his fist.
Continuity mistake: During the execution scene when Wallace is reflecting and sees his wife in the crowd. Pay attention to the axe as it is coming down on Wallace's neck. As the axe approaches, it slows down as it gets closer. The scene is in slow motion, so look close. [According to Mel Gibson, the executioner actually placed the axe near Wallace's head and then raised the axe. The scene was shot in reverse for the movie. Doesn't make it less of a mistake, but explains it - the axe was accelerating, so in reverse it looks like it was slowing down]
Continuity mistake: In the scene where Wallace and Hamish are discussing throwing rocks while at the wedding, the shots alternate between their faces, depending on who is speaking. From one angle their hair is blowing in a breeze, from the other angle the wind is calm.
Continuity mistake: At one point, when a bit player escorts Wallace's friend away, he utters his only line without a Scottish accent. Someone from southern California must be visiting Wallace's army.
Continuity mistake: When Wallace is at his brother and father's funeral at the start of the film, Hamish's and Murron's father are both in attendance. Let's say that this is about 20 years prior to the first battle at Stirling in 1297. 17 years later, the battle at Bannockburn takes place, yet Murron's father is fighting in it, looking not a day older than at the funeral scene which was supposedly almost 40 years prior to it. And when Hamish's father dies at Falkirk, he looks no older than at the aforementioned funeral scene. A miracle anti-ageing cream perhaps?