Continuity mistake: In one of the major battles, Wallace is charging down a hill with a large sword in his hand. During the charging it changes to being a small pick axe type tool. Then around the middle of the charge there is a quick shot change and almost from the same angle the pick axe has disappeared. It then changes back to a large sword, a quick change back to the pick axe, then back to the large sword.
Continuity mistake: In the first large battle with England at Falkirk the same scenes are used when the English fire the arrows. The first time the arrows are fired, a blonde young man is hit in the foot, they then moon the English so they fire again and the same man is seen getting hit in the same foot. A man in the same battle is shot in the hip - when he grabs the wound you can see the shape of the cushioned bulb that the arrow is attached to. If you watch during all the battle scenes you can detect men who are supposed to be on opposite sides standing and talking, also you can see the choreographed moves being played out in almost slow motion - their swords aren't even striking.
Revealing mistake: At the end, Wallace's friend is charging in slow motion, and if you look closely you will see his battle axe flopping around like it's made of rubber.
Continuity mistake: In a major fight scene two soldiers on opposite sides are jumping and spinning and tapping each other on the head with their swords.
Other mistake: When Robert the Bruce returns to the battlefield at Falkirk, there are 2 children supposedly crying over a loved one. If you look at the blonde girl she is actually laughing.
Continuity mistake: At the end when Wallace is being led to be executed, he is pelted with food. Much of it sticks to his face and hair. A few moments later when they are standing him up he is completely clean.
Revealing mistake: After Wallace kills the Scottish noble in bed, he jumps out of the castle window into a river on a horse. As he is falling, you can see that the horse is a model and when they fall into the water one can see the fake horse bobbing around.
Continuity mistake: At Stirling an English archer is hit by the nobles on horseback causing his helmet to fall off. He's then hit again and somehow his helmet falls off again. Then when he lands he is still wearing his helmet despite it having fallen off (twice).
Continuity mistake: When the English spy tries to kill Wallace, and you realize the crazy Irishman is a friend, you see the spy drop his sword, as soon as he is hit by the Irishman's weapon, but as soon as he hits the ground dead, the sword is back in his hand.
Continuity mistake: When Wallace tries to escape from the English with his wife, not knowing that she has been captured and executed, he is seen running through the woods screaming her name... As he's running he has a sword in his right hand. During the course of three or four camera shots, the sword he is holding magically disappears and reappears as different cameras shoot him. Then it reappears and he digs it into the ground as he takes off the English soldier's uniform that he stole.
Visible crew/equipment: In the execution scene at the end, right as Wallace is being quartered, you can clearly see (on widescreen) a plastic spray bottle on the upper left part of the screen, presumably filled with fake blood.