Continuity mistake: Several times during Heywood's speech to the team at the moon base, his arms shift from his sides with hands in pockets to in front of him with hands on the podium.
Continuity mistake: The view of the front of the moon buggy shows the sunlight coming from the right side of the screen(Pilot's left shoulder) But when we see his view out the window, the sunlight casts shadows as if the sun was behind them.
Continuity mistake: The Discovery's crew quarters has five beds, three for the hibernating crew, two for the Bowman and Poole. The exact beds occupied by hibernating crew changes from one scene to the next. This error is caused by Frank's last two running shots (the ones where the camera stayed just ahead or just behind him as he ran) having been accidentally reversed in editting. Frank's hair is parted on the wrong side and the sleep tube layout and the body positions within are precise mirror images of the layout seen in all prior and following shots.
Continuity mistake: When Frank receives his parents' birthday message he is relaxing on the sun-bed. As the message drags on there is some intercutting with various other views about the room. One shot happens to be of the sun-bed from an alternative angle, and Frank is nowhere to be seen. In the next shot Frank is once again lying on the bed.
Continuity mistake: When the astronauts are approaching the monolith on the moon, the earth is clearly seen in a gibbous phase near the horizon. In the next scene, the sun passes behind the earth, which is now in a "new" phase overhead. The earth does not change its position in the lunar sky, and certainly cannot change phase that fast.
Continuity mistake: When Floyd and his team are heading to the Lunar excavation site, they start to eat those synthetic sandwiches. One of the shots shows a closeup of Floyd. As he is right about to take a bite, the camera cuts back to a shot of the three men. However, Floyd's sandwich is instantaneously about a foot from his mouth and he is fully chewing. (00:47:50)
Continuity mistake: For most of the sequence during which the Orion space shuttle closes in to dock with Space Station One, we see the space station rotating counterclockwise, as viewed from the side the Orion is approaching. But the first two times we see the station (immediately before and immediately after the scene in which Floyd's pen floats free aboard the Orion), it is rotating clockwise. It is also apparently rotating clockwise in the shot from inside the station, looking out at the approaching Orion. The stars in this shot are turning clockwise, implying that the station is moving anti-clockwise, hence must be rotating clockwise when observed from the Orion.
Continuity mistake: On board the Aries Moon Shuttle is the famous scene when the Pan Am flight attendant serves a meal to Dr. Floyd and then retrieves additional meals, enters the doorway and walks 180 degrees up the wall and over to be upside down to deliver the meals to the shuttle pilots. However, from the outside view of the spacecraft, the pilots are sitting perpendicular to where the passengers sit and she should only have walked up the wall 90 degrees.
Continuity mistake: Frank is running around the centrifuge. He passes the ladder with two bunks to the right and the work station to the left. When Dave comes down the ladder, the bunk is to the left. This error is caused by Frank's last two running shots (the ones where the camera stayed just ahead or just behind him as he ran) having been accidentally reversed in editting. Frank's hair is parted on the wrong side and the sleep tube layout and the body positions within are precise mirror images of the layout seen in all prior and following shots. (00:56:50 - 00:57:55)
Continuity mistake: When Dave begins to disconnect HAL's circuits, one angle shows him unlock the first, second, then third unit. Just as he's about to remove the key from the third lock, the angle changes and he's pulling the key from the second lock and then goes for the third again. We know this is consecutive time as HAL is pleading with Dave the entire time. (01:51:45)
Continuity mistake: When we see the outside of the cave where the apes are sleeping for the first time it's at sunset. We can see the sun and cloud behind the cave as if it is just sitting in a rock face with nothing behind it, but in the next shot when it's daytime suddenly there is a background of rocks and mountains behind the cave.
Continuity mistake: When Frank Poole and Dave Bowman are discussing with HAL the possibility of HAL being in error predicting the AE-35 Unit fault, the 10x3 grid of buttons on the console in front of them is lit differently depending on whether the shot is from behind the men, or in front of them. (01:20:40 - 01:23:00)
Continuity mistake: In the scene where HAL is reading the lips of Bowman and Poole through a pod window, while they are in the pod discussing his possible disconnection, they are shown to be directly facing each other, keeping their heads perfectly still, while HAL looks back and forth from mouth to mouth. In the previous scene, the two men were not conversing in this unusual manner.