The movie Blade Runner is a pretty substantial departure from the Phillip Dick book "Do Robots Dream of Electric Sheep" on which it was based. Even so, and perhaps uniquely in literary history, Dick seems to have absolutely loved the movie. It kept the right elements of the book - ie, what makes us human -- and shed the silly, trippy stuff.
I don't remember it being a huge box office success. Probably too dark, even with the last minute change of ending (the happy notion that Rachael had no programmed termination date was added to give audiences a more upbeat ending.) But the movie certainly had a huge effect on the look and feel of sci-fi. After the Matrix and the Terminator, we are used to future dystopias, but in the 1970's most popular sci-fi had cities that were as bright and shiny as a new penny. I remember seeing it the first time, and Blade Runner was arresting, a whole new category of sci-fi noir. I still love the movie, and it wears pretty well, but nowadays fan argue endlessly of the merits of the original release vs. the directors cut. The latter purges the Harrison Ford narration and happy ending that were tacked on to make the movie more audience friendly. I personally like the narration-- it feels consistent with the noir genre -- though the faux happy ending is lame.