Scott originally filmed without the voice-overs, but due to its poor reception at sneak previews in Dallas/Denver and San Diego, the studio insisted that the voice-overs be added. Scott said in an interview on American television that in film noir, voice-overs sometimes work, and sometimes don't, and they didn't work in Blade Runner.
(A)n extensive voice-over was added to help people relate to Harrison Ford's
character and make following the plot easier. (A)fter a draft by novelist-
screenwriter Darryl Ponicsan was discarded, a TV veteran named
got the job. As finally written, the voice-over met with universal scorn
from the filmmakers, mostly for what Scott characterized as its 'Irving the
Explainer' quality.... It sounded so tinny and ersatz that, in a curious bit
of film folklore, many members of the team believe to this day that Harrison
Ford, consciously or not, did an uninspired reading of it in the hopes it
wouldn't be used. And when co-writers
Fancher and Peoples, now friends, saw
it together, they were so afraid the other had written it that they refrained
from any negative comments until months later.
- Los Angeles Times Magazine, September 13, 1992.
The ending of the film was also changed by the studio. Scott wanted to end the film with Deckard and Rachael getting into the elevator, but the studio decided that the film needed a happier, less ambiguous ending. The aerial shots used in the 1982 theatrical release were outtakes from Stanley Kubrick's The Shining (which, coincidentally, featured Joe Turkel).
In September 1992, Warner Bros. released a new version of Blade Runner: "The Director's Cut" ( BRDC), which eliminated the voice-overs and the happy ending.