Continuity mistake: After Gordon gets dragged across the sand by the magnetic collar, he lies 30 cm away from it, his right arm straight. Then West shows up, and angle back to Gordon, who's now just 10 cm away with his arm bent. If he had dragged himself upwards between shots sound had had to be heard.
Continuity mistake: Gordon's train dodges Loveless' train-tank shot by going around a bend. In the shot right after the dodge, we should see the bend that they just passed, but all we get is more straight tracks.
Continuity mistake: When Arliss Loveless makes his appearance at a gathering, a giant bust of Abraham Lincoln is wheeled out. The head on this bust explodes and we see Loveless's head pop out in place of where Lincoln's was. When we see a close up of it, we see what was left of the bust around Loveless's head, yet instantly afterward in a wider shot, the remains of the bust disappear.
Continuity mistake: After the cornfield scene and the heroes fall into the mud river, their clothes and metal collars are seen to be covered in mud. In the next scene featuring them, their clothes are muddy but their metal ring collars are totally unmarked.