Revealing: You can see the studio floor in the "white void" outside the TARDIS door in early shots during episode one of this story.

Other: William has a bit of a nightmare, completely throwing the others during one scene by saying the same line ("It's not very likely") twice, and fumbling the line "You knocked both Susan and I unconscious". He also omits the scripted explanation for the melted clocks.

Continuity: Susan's socks disappear during the opening credits.

Audio problem: During Hartnell's big speech about the creation of a solar system, a cough can be heard from off-stage.

Visible crew/equipment: When Susan runs out into the console room in a panic, the shadows of two crew can be seen on the wall.