Visible crew/equipment: At the end of the movie when the family returns to their burned down home, they find their friends rebuilding it. After they all talk, the camera moves back slowly as the family walks forward. To the right, across the field, you can see a line of cars, trailers and tents for the cast and crew, all parked either on a road or amongst some trees.
Factual error: When Benjamin is trimming bullets he makes from toy soldiers, the tool he uses to trim them has a manufacturer's stamp on the handle, not something that should be there in this time period.
Revealing mistake: Gabriel is noticeably breathing when he is supposed to be dead.
Factual error: In Gabriel's letter, he says his friend fell at Elizabethtown. The battle, which was actually the battle of Monmouth in NJ, was fought in June 1780, but when they show him getting shot it is blizzard conditions.
Factual error: Mel Gibson's son has toy soldiers from the future. In one shot when he is melting one of the soldiers it is visible. Although it has a red uniform it isn't a British soldier. In fact it depicts Hofburg Trabanten Leibgarde which was the personal guard of the sovereign originally from Austria, in uniform from around 1850 - 1918. (01:10:55)
Factual error: Throughout the film, all the women are running around without "modesty pieces," a scarf/shawl that would cover their shoulders and tuck into the front of their dress, so their breast tops were not exposed.
Deliberate mistake: The Americans actually spoke with American accents, but these very new Americans were British in origin, and so they couldn't develop a new accent in such a short time. The Americans should still have British accents. This would have been confusing and is done for the viewer's benefit, but still a mistake.
Continuity mistake: Right after the scene where Benjamin Martin attacks the British army for the very first time to save his son, Col. William Tavington is interviewing the only survivor of the attack in a tent in a British camp. His green collar keeps popping in and out from under his leather strap over his right shoulder.
Continuity mistake: When Gabriel wakes up after having had his wound treated he lifts his hand, covering his eyes. When it cuts his hand is suddenly on his forehead. (00:24:35)
Continuity mistake: At the end when they are returning to the homestead, in one shot, Charlotte holds a baby in her left arm, followed by a shot of one of the boys. In that shot, Charlotte's left arm is hanging to her side with no baby.
Continuity mistake: When Gabriel is pulling his knife out of the dead British soldier, there is a long piece of grass on it. It shows Col. Tavington's body on the ground, then it shows Gabriel holding his knife again, and the piece of grass is gone. He is also standing in the same position as before, so it seems unlikely that he pulled the grass off the blade.
Factual error: During his preparation for the final battle Benjamin is making a bullet using a pair of Rapine bullet mold pliers. According to their records the Rapine Mold Company was not established until 1964.
Visible crew/equipment: When Gabriel approaches Anne and she tells Gabriel, "You know who I am, Gabriel Martin." At the end of this shot you can see at the top of the screen a microphone moving back and forth.
Continuity mistake: After Benjamin and his sons ambush the British troops, a surviving British soldier is holding a knife to the left side of Gabriel's neck threatening to kill him. Benjamin throws his axe in the soldier's head, and he falls to the ground, but cuts Gabriel on the neck. As he falls, the knife drags along the left side of Gabriel's neck, but the cut is on the right side of his neck.
Continuity mistake: Tavington does a fast reload and adopts a duelist's stance, i.e. side on so as to make a smaller target. Gabriel shoots him and Tavington falls. We later see that Tavington is only creased on his left side which is strange since Gabriel could not have hit him there since it was the side farthest away from him.
Continuity mistake: After Garbriel gets married, there was a wedding party. During the party you can see a slave playing a xylophone-type instrument while a boy stands next to him. However, when Benjamin is talking to his new daughter-in-law, the slave can be seen in the background while the boy is nowhere to be found.
Continuity mistake: In the battle scene where the cannonball rolls through taking out the troops legs. Watch it frame-by-frame, two legs are shown close up to be taken out by the cannonball. Both explode at the time it passes through the first leg, not as it hits each one.
Continuity mistake: When Gabriel dies his head is facing straight up looking at the sky. then they cut the scene and show Ben then they show Gabriel again and this time he is facing his father.
Revealing mistake: During the battle at the end, while Martin and Tavington are fighting, you can tell the battle going on behind them is a blue screen because they are often moving slower than the battle and vice-versa.
Continuity mistake: As Benjamin's milita walk onto the battlefield on the morning of the final battle, we see many shots of the soldiers. One soldier has a bloody bandage around his forehead and blood running down his face. This is early morning and there didn't seem to be a battle the previous day. Why is he bleeding, and why wasn't it cleaned up during the night?
Answer: I think the one you want is 'Unseen' - By Craig Armstrong which is track 2 on the Plunkett and Macleane soundtrack.