During the production, MGM opted not to shoot the "nightmare train" sequence to keep costs down. H.R. Giger was not willing to accept that, however, so he spent one hundred thousand dollars of his own money to finance the sequence.
Michael Madsen once claimed this was one of the few movies he had done that he was proud of, but referred to the film's sequel as "lousy" and admitted he only did it for a paycheck.
Frank Welker, who provided Sil's alien sound effects, said it was one of the most strenuous on his vocal chords with the various types of screaming and screeching sounds he was asked to create, but he had a lot of fun regardless.
In the commentary, Michael Madsen says Ben Kingsley was protective of his chair on set and didn't like anyone touching it. Kingsley said Madsen would purposely do things to it, including dumping garbage on it and hanging it from a crane.