A special-effects sequence that took place at the beginning of the film was cut shortly before the movie hit the theaters. In this sequence, the carnival materializes from the smoke of the train - the smoke from the engine "becomes ropes and canvas tents. Tree limbs grow together to form a ferris wheel and a spider web mutates into a wheel of fortune." This sequence was the first time that computer animation was used to animate organic material, and it was combined with traditional animation. The scene was deemed not convincing enough and was cut from the film at the very last minute (according to an issue of "Twilight Zone Magazine" that was released the same month as the film, the scene was going to be in the final print).
In the spider sequence, the boys are noticeably older, since the scene was re-shot after the rest of the production had been completed. This was used to replace a sequence with a large mechanical hand which, like the animated appearance of the carnival, was deemed too hokey and was subsequently cut from the film.
Disney made many changes to the film that Ray Bradbury and director Jack Clayton did not intend. Many extra special effects scenes were shot, and other changes were made before its release. According to the laserdisc commentary by Bradbury, much of his original intentions for the movie were destroyed.
In Anchor Bay's DVD, the end of the theatrical trailer (which shows the film's title) has been cropped. The rest of trailer is in 1.85:1, but that last shot is around 2.35:1, which has caused confusion among fans. This aspect ratio change in the trailer was done by Disney to mask off Disney/Buena Vista names. Disney did not allow its name anywhere on the DVD package.
Ray Bradbury first wrote 'Something Wicked This Way Comes' as a screenplay in 1952, after watching Gene Kelly in Singin' in the Rain (1952), which Bradbury thought the greatest musical ever made. Bradbury showed Kelly the screenplay, and Kelly was so impressed that he wanted to make it his next picture. When Kelly shopped the story around to potential backers, however, he was unable to raise any money for the project. It was only after this failure that Bradbury rewrote the story as a novel, which was published in 1962. Bradbury dedicated the novel to Kelly.
The lines "And in despair I bowed my head / "There is no peace on earth," I said, / "For hate is strong and mocks the song / Of peace on earth, good will to men." / Then pealed the bells more loud and deep: / "God is not dead, nor doth He sleep; / The wrong shall fail, the right prevail / With peace on earth, good will to men" is from "I heard The Bells On Christmas Day" by Henry Wadsworth Longfellow.
The music for the film was originally composed by Georges Delerue, but it was rejected by Disney for a less somber score, and was replaced by James Horner's more upbeat score. Portions of Delerue's score can be heard in the film's theatrical trailer.
After a poorly received test screening, Disney held back the release of the movie for a year to re-edit it, film additional and replacement scenes (including special effects sequences), add an opening narration, and hire James Horner to rewrite a completely new score, all of which added millions to the budget. It's quite obvious when watching the film which scenes, such as the spider attack and the mirror maze climax, were filmed a year after production had initially wrapped. Reportedly Bradbury and the film makers were not pleased with the studio's intervention nor the effects it had on the picture, which ended up being a flop when it was finally released in 1983 despite Disney's attempts to make it more audience friendly.