It was a wise decision by the BBC regarding this longer installment of "Dr. Who," featuring William Hartnell, not to try for overly elaborate visuals. Because of that choice, throughout the seven episodes of this story, attention could be given to building out the personalities of Hartnell’s character and those of Susan, played by Carole Ann Ford; Barbara, portrayed by Jacqueline Hill; and Ian, who is William Russell. The TARDIS arrives in a woodland area that appears devastated, like it had been struck by some kind of nuclear event. Following a short look around, the companions are eager to leave, but the Doctor is more interested in investigating, pretending there’s something wrong with his time machine. Soon they find themselves in a city populated by Daleks, where people are ill from radiation and being employed as bait to draw out the Thals—presumably to their destruction. The visitors quickly understand that they need to escape and alert them before hearing that familiar "exterminate" command! What follows introduces one of science fiction’s most inventive and memorable villains; although it does occasionally feel slow-paced, the story remains fairly captivating to watch, with Hartnell giving a wonderfully peculiar performance. There's a slight suggestion of moral lessons but this doesn’t linger long before Alydon, played by John Lee, and his group decide to put aside their internal struggles and begin fighting their dangerous enemies, leading to an exciting finale that is, regrettably, somewhat foreseeable.

Source on TMDB