This contains the first instance of Klingon opera in the series, as well as Worf's avid appreciation for it. There were further mentions of it in Star Trek: Deep Space Nine (1993).
Malachi Throne (Senator Pardek) was also with Leonard Nimoy during his first Star Trek (1966) pilot The Cage (1966), as the voice of the Talosian Keeper. Throne also played Commodore Jose Mendez in The Menagerie: Part I (1966) and The Menagerie: Part II (1966).
The four-handed pianist "Amarie" is played by Harriet C. Leider. Her dialogue and singing were re-recorded in post-production by Judi M. Durand, who later went on to perform the voice of the station computer on Star Trek: Deep Space Nine (1993).
As with Unification I (1991), a title card ran before the teaser in tribute to the late Gene Roddenberry.
This episode aired about a month before Star Trek VI: The Undiscovered Country (1991), and makes reference to the actions of both Spock and Sarek in that film.