Continuity mistake: A UFO crash lands in Canada and sits amidst trees in a wooded area. Just before the craft explodes, the only snow visible is on mountains in the distant background. After it explodes, however, the ground and trees all around it are suddenly covered with snow.
Continuity mistake: "Kill Straker": When Straker grabs the gun from Foster, we can see a man in a spacesuit outside Moon Base's control room window. But in an establishing shot just before this, we saw an exterior shot of the base, including that window, and the spacesuited man was nowhere in sight.