In a 2004 interview, Margot Kidder claimed that Richard Donner shot enough scenes to make his own cut of the film, and that the unused footage was "somewhere in a vault." A website started a petition for Warner Bros. to allow and sponsor Donner's cut of this movie. The footage was re-edited into Superman II: The Richard Donner Cut (2006).
Gene Hackman did not return to do reshoots for the second film. All of his scenes were originally filmed by Richard Donner. Other scenes shot by the new director that required Lex Luthor used a look-a-like and a voice impersonator to add any lines needed.
During one take of the shot in which Lois punches Ursa, Margot Kidder accidentally punched Sarah Douglas and knocked her unconscious.
Despite Lex Luthor always being depicted as bald in the comic books, Gene Hackman refused to wear a bald cap for the movies. So it was agreed that he would instead wear a series of ill-fitting wigs that would imply baldness. Hackman relented to wearing the bald cap for the prison scenes, however, as it was unfeasible that Luthor would be allowed to keep his wig collection while locked up.
Eve Teschmacher disappeared from the storyline after she and Lex Luthor leave the Fortress Of Solitude, and her absence from the rest of the movie is never explained. This is due to Valerie Perrine's scenes being filmed by Richard Donner, who was fired from the sequel before completion.
Richard Donner: (at around 1h 18 mins) Walks out of frame during a point-of-view shot as Lois and Clark pull up to the diner.