The original 1982 cut of the movie featured a score by Michel Legrand. When the movie was re-edited and subsequently re-released in 1984, it was replaced with a more science-fiction-laced score by Morton Stevens (of Hawaii Five-O (1968) fame). A soundtrack LP was released containing on one side the score by Stevens and on the other side highlights of the score by Legrand.
The "making" of this movie: can be found on YouTube.
During the twin's food fight scene, each has a can of Sugar Free Dr. Pepper.