Changes in Star Wars re-releases vary from minor differences in color timing, audio mixing, and take choices to major insertions of new visual effects, additions of characters and dialogue, scene expansions, and replacement of original cast members with newer ones. Though changes were also made to the prequel trilogy, the original trilogy saw the most alteration. Dissatisfied with the original theatrical cuts of the original Star Wars film, The Empire Strikes Back, and Return of the Jedi, creator George Lucas altered the films in ways that were ostensibly not initially possible, primarily due to limitations of time, budget, and technology.