When the Doctor opens the door to leave the TARDIS, the cave wall is visible behind him, revealing the prop to have no back.
The actor playing Koquillion wasn't wearing the character's feet when it stepped on to Vicki's ship.
After Koquillion throws Barbara over a ledge, she can be heard screaming before she opens her mouth.
After the Doctor says that he was going to.have a look at the TARDIS console, a studio cable can be seen behind him on the floor.
When Barbara asks the Doctor to let her open the TARDIS' door, a boom mic shadow appears on Ian's forehead.