Ridley Scott had already crafted a groundbreaking, visually impressive sci-fi masterpiece with Alienin 1979. But Alien was really more of a horror movie, a unique science-fiction spin on the "Monster in the House" genre. Blade Runner is a movie that raises more philosophical questions.
When making the movie, Scott helped chart its visual style and groundbreaking set design. He took inspiration from the futurist artist Syd Mead as well as from the cult magazine Heavy Metal (which itself was adapted into a corny R-rated cartoon film). When he finally finished the movie, the story goes that Scott began with a four-hour version of the film: according to him, he thought it was great, but he didn't know what it meant himself (source).
And, oh—the dude totally clashed with Harrison Ford the whole time and got into a T-shirt-based sparring match with the American film crew, after comparing them unfavorably with British film crews (who always said "Yes, Guv" and did what they were told promptly, according to Scott). The American crew printed out T-shirts with "Yes, Guv" printed on the front, which led to Scott wearing a T-shirt that said "Xenophobia Sucks" on it. You do what you gotta do, we guess (source).