Features the first appearance of a humanoid Cylon, a concept that would be more fully explored beginning in Battlestar Galactica (2003) and Battlestar Galactica (2004)
This episode takes place from October 30 to October 31, 1980.
The Halloween backdrop to the Cylons (i.e. alien) landing and attempted invasion was likely inspired by the Orson Welles radio drama War Of The Worlds.
Near the end, Shirley Blore gets out of a car and says "I'm not really a vampire. I'm in a costume, just like you. We are going to a party." Shirley Blore is played by Lara Parker who played the witch Angelique Bouchard Collins, who at one point, was a vampire, & Catherine Harridge Collins, among other characters, in Dark Shadows (1966) TV series.
This episode was reportedly originally to be a single show followed by another one entitled, "So this is New York" instead it became a 2 part episode and the second title, became one of Lt Dillon's last lines in the final scene of part 2.