The model used in place of the Voord falling to its doom turns sideways as it falls, revealing that it is a two-dimensional cut-out.
After the Doctor turns his dial and disappears from the room, the shadow of his right elbow is still on.the wall.
When Ian tries to prise apart the cage bars, one clearly moves showing it isn't attached at the top.
While Arbitan is talking to the Doctor for the first time, the camera shakes slightly when it is zooming in.
William Hartnell flubs the line "If you think I'm going to travel across that acid sea in one of these primitive submersibles, you're very much mistaken."
When the Voord falls through the pyramid revolving wall, a stage hand can be seen briefly on the other side.
When Ian is first inside the pyramid, someone stumbles through the background.
After the Doctor goes into the pyramid, someone's leg appears on the lower right side of the screen just before the shot ends.
Two shots after the Doctor goes through the pyramid's revolving wall, just after Ian peers around the corner, the shadow of a boom mic can be seen behind them.
As Barbara enters the pyramid through the revolving door, a hand can be seen moving away from the left side of the screen.