The title of this episode references The Beatles' album "A Hard Day's Night."
Peter suggests the Rainbow Room or clubs in "The Village" to Doris. The Rainbow Room is an upscale restaurant and nightclub on the 65th floor of the GE Building in Rockefeller Center, Midtown Manhattan. "The Village" is a nickname of Greenwich Village in Lower Manhattan.
Genevieve, Sir Bruce Sans Pitie, and Merlin are all figures in Arthurian history. However, Genevieve is better known by the Anglicization of her name: Guinevere.
Sir Bruce refers to his soldiers as "bully boys." Of several meanings, it can mean a tough guy or hired thug.
Although entirely a coincidence, this episode shares several plot elements with Ghostbusters II:
-A date gone wrong
-A recently unveiled painting
-The main villain comes from a painting
-Magic anchors the villain to a painting
-Peter's love interest is taken captive
-The Ghostbusters rappel into a museum
-The Proton Streams initially fail against the villain
-A victim is placed before a painting