During his dinner with Quigley, Marston describes his 1860 Colt Army revolver as a "recent invention" of Samuel Colt's. However, Quigley's own weapon is an 1874 Sharps rifle, therefore by the time the story takes place Marston's weapon would be relatively archaic. In fact, the 1860 revolver was superseded by Colt's 1873 pattern, a ten inch barrel version of what later became known as the "peacemaker", the first Colt pistol with a bored-through cylinder taking a centrefire cartridge. Given Marstons infatuation with everything American, it would have made far more sense for him to be equipped with the 1873 model, which would better qualify as a "recent invention".
In the distant shot of Quigley tying his bandanna around his wounded leg, the sun is just about to set behind a hill. Just before and after that shot, the shadow of his hat falling on his face and shoulders shows that the sun is high overhead.
When Quigley kills the man after they are dumped in the desert, there is a drastic difference between the shadow on the dead man's face between the moments just before Quigley shoots and after he shoots.
While the dingoes are advancing on Cora and the baby in the cave, and she is reloading the revolver and, the right shoulder strap on her blouse keeps falling down, and then reappears on her shoulder in the proper place all by itself.
When Quigley shoots the bucket to prove his marksmanship to Marsden, the vernier sight is at different settings during the three shots fired. First in the middle. Second shot (close-up) shows at bottom. Last shot shows somewhere above middle. At the distance he is shooting, it should be at or near the top causing the end of the barrel to rise making the bullet follow an arc to the target.
When Quigley is preparing to ride out to face Marston in the final showdown, He tells Cora that she sure looks good in the morning sun. The sun is over the ocean, in western Australia, which makes it the *setting* sun. The morning sun would be over land.
While the rifle used by Quigley fires a supersonic round, it decelerates quickly. At ranges less than 300-400 yards, the bullet would arrive sooner than the "bang", but only by a fraction of a second. At ranges greater than this, the sound of the shot would arrive before the bullet. Thus, there would never be a point where the sound of the shot would follow the bullet by several seconds.
Quigley and Crazy Cora are taken to a camp by the native Aboriginal people. There they chant and play a Didgeridoo. In this part of Australia, Western and Central there are no didgeridoos. The Yirdaki and Mago Didgeridoo are endemic to only Arnhem Land. In the Western part they use Mago, in the North East part they use Yirdaki. This is at the very northern part of Australia, in a small delimited area. When this scene was cited to have taken place none of the the central and western Aboriginal Australians, namely in the desert, used a Didgeridoo in playing music. Only in later times has it spread more though out Australia.
In the close-ups with the sun overhead, and the shadow of his hat falling on his face and shoulders, there is a second shadow of the brim of the hat on his forehead, revealing the presence of another light source.