Factual error: The 80 foot mechanical spider leaves Arches National Park and seems to get to Promontory Point in almost no time at all - that's 312 miles.
Continuity mistake: When Will, who is black, is in the carriage, he is the only person on it. When you see a close up of the horses, you can see a white persons foot dangling from the carriage.
Factual error: At the beginning of the movie, we see that the scientist who was killed was wearing his glasses. Hence, his last image would have been a clear one. Of course, the whole process of projecting a man's last sight by means of a light shone through his retinas is preposterous.
Continuity mistake: As the tank pulls out of the lagoon, it has no seaweed on it until it is fully out of the water.
Character mistake: When Gordon describes Leonardo Da Vinci's idea for a flying machine, he mentions Da Vinci designed it in 1540. However, designs for Da Vinci's flying machines were dated as early as 1488 and Leonardo Da Vinci died in 1519.
Factual error: As Jim and Artemus leave the White House heading for the Wanderer, they both head south. However, if they're taking a train from Washington to the west in 1869, they've got to use the B&O's track. The B&O station was north of the White House.
Continuity mistake: When Kevin Kline hits Will Smith's metal collar after jumping in the mud, they become magnetised and Kevin's collar sticks above Will's. In the next scene Will's is on top.
Factual error: In one scene Jim West is walking up to the White House. There is a cast-iron gate surrounding the White House, as there is today, but he gate was not added until the 1930's.
Factual error: The nitroglycerine would have exploded when McGrath's men threw it roughly onto the cart, leaving no risk of it exploding later when West makes his comment that this is not the way you transport nitro.
Continuity mistake: In the cornfield, Gordon grabs a note with his right hand. A shot later he holds it with his left hand.
Continuity mistake: Jim arrives at the White House and a man stops him, placing his hand on Jim's chest. A shot later his arm is lowered.
Continuity mistake: When Loveless appears under Lincoln's bust, he has debris on his shoulders, which disappears in the following shot.
Continuity mistake: When Lincoln's bust explodes a pinkish piece of debris lies on the neck part. When Loveless appears, the debris disappears.
Continuity mistake: While West is having a bath, an old man walks towards the carriage with a crate. He stops and swings it backwards to increase momentum. When the shot changes he is walking towards the carriage again.
Continuity mistake: After Gordon is punched on the face, he pinches his nose, raises his hand and tells Lippenreider "Wait." From the opposite angle his arm is lowered.
Continuity mistake: In the Spider, after West punches Loveless his hair gets messed-up. In the following wide angle where Loveless kicks West his hair looks fine.
Continuity mistake: In the Spider Tank, when the iron man dies and falls backwards, the way West grabs himself onto the column differs between the front angle and the angle shot from behind.
Continuity mistake: On the Spider Tank West is fighting against an iron man. West walks backwards pass two columns and stands by the column on his right. From the opposite angle he is standing by the column on his left.
Continuity mistake: During West's fight with the crew of the Spider Tank, he is launched face-front, but in the close-up he falls on his back.
Continuity mistake: When West is fighting against a man with a blade in each hand, a close-up of West's shoe shows it's surrounded by a wooden floor. In the following angle the foot has an iron platform behind, despite West not having moved.
Answer: Assuming it's the same technique used for Gary Sinse in Forrest Gump, Mr. Branagh was probably wearing blue leggings which was used to digitize out his legs.
Lisa T Ellis