When Lucas McCain and Blade Kelby are fighting near the stagecoach, from shot to shot the action shifts from an outdoor setting to an obvious soundstage and back outdoors again.
When Johnny Cotton gets the jump on McCain from atop a high area on rocks, he is sitting with his right knee up and left leg flat on the rock. When the shot goes to a close up, both knees were up. In addition to that, from afar he says "Hi McCain" though his lips do not move.
Lucas's hat gets knocked off twice. When Blade goes down to check on Lucas after Cotton shot at him, a fight breaks out. In one shot, Blade hits Lucas and he falls back into some brush and his hat comes off. He gets up and the camera changes and, all of a sudden, his hat is back on his head.
When Kelby is dumping out the coffee from the pot, Lucas sees it glint in the sun. However, there are no shiny surfaces on the pot to glint. A few minutes later, the cylinder on Kelby's handgun falls off when it hits the rocks. There is a pin under the barrel that holds the cylinder in place, so it is impossible for it to fall apart so easily.
During the fight between Lucas and Blade Kelby (Gregory Walcott) Kelby's gun is knocked out of his hand and lands muzzle pointing up on some rocks. When Lucas finds it the cylinder has been knocked out of the frame and is down in the rocks. The cylinder base pin is still in the frame. Without the cylinder base pin being removed there is no way possible that the cylinder could be removed including an extremely hard blow to the cylinder.
As the stage pulls away leaving Lucas behind before he starts his search for the three robbers. Later Lucas is seen descending a rocky incline. He now has a canteen hanging from his shoulder. He did not have a canteen when the stage first pulled away.
When McCain is tracking Johnny Cotton & Abe Jordan he sees them from above on top of a cliff as outlaws are riding below. he pushed a few (10-15) rocks over the ledge and, all of a sudden, it turns into a major landslide much wider than where McCain was pushing. The rocks in the landslide are darker and much larger (and more numerous) than what McCain had pushed. In addition, it is not the same cliff when the larger rocks are shown.