When Lady Hamilton says to Nelson, "Don't leave your Emma alone and deserted", her left arm is up, as if her hand is on his face or shoulder; a split-second later it is down at her side.
The guns on HMS Victory seem to be of a single size. In particular, the guns on the upper deck are bigger than they would've been. The Victory had three main gun-decks. The guns on the lowest deck were 30-pounders, those of the middle deck 24-pounders. The guns on the top deck were relatively small 12-pounders. This arrangement was to ensure that the ship didn't become too top-heavy, and thus unstable.
When the cannons on the H.M.S. Victory fire through the gun ports, there is no recoil from their blast.
Despite being popularized as such by previous films, Admiral Horatio Nelson never wore an eyepatch. Despite having lost the sight of his left eye during the Siege of Calvi in 1794 after a cannonball hit a sandbag near his position, blasting sand and debris on his face, he did not lose the eyeball. Nelson did have a visor sewn to his hat that partially covered his blind eye, to protect him against glare, but never wore a full eyepatch, especially on land.