Other mistake: When the captain comes face-to-face with the Thing for the first time, the upper right frame becomes blurred once the door starts opening until it closes followed by a scene change. Very odd except maybe they were trying to hide the minicharges to create the bullet holes after they close the door. The implanted charges are very visible when the scene is not blurred. Also there is a small charge in the wooden frame of the door near the door handle. (00:57:32)Larry Koehn
Other mistake: When one of the Christians is being crucified and burnt, we can see that just after the man's "death" the body is substituted by a plastic doll covered in red paint.
Other mistake: The day after informing Lady Barbara that he was married, Hornblower, in a rush to get home, orders the t'gallants set. But the ship, as shown in the prior scene, already has them set.