Trivia / Star Trek: Deep Space Nine S02E23 "Crossover"

• Acting for Two: Avery Brooks, Nana Visitor, René Auberjonois and Colm Meaney all play their regular characters and their Mirror Universe counterparts.
• Sequel Gap: This episode was produced 27 years after "Mirror, Mirror".
• What Could Have Been: Mirror Garak's role as Intendant Kira's treacherous underling was originally intended for Mirror Worf (before Worf joined the DS9 crew) but Michael Dorn was unavailable due to this episode being filmed at the same time as TNG's "Firstborn", in which Worf had a key role.