The shots where Luke uses his Jedi powers to retrieve his lightsaber from a distance were achieved by having Mark Hamill throw the lightsaber away, and then running the film in reverse.
In order to avoid sharing creative rights, George Lucas decided to avoid using a major studio to finance this movie. Instead, he bankrolled the $30 million production himself, using a combination of his profits from Star Wars: Episode IV - A New Hope (1977) and a bank loan. Although the move was risky, it paid off several times over. Lucas recovered his investment within three months of the movie's release. He then showed gratitude far beyond the Hollywood norm by sharing the profits with his employees (nearly $5 million in bonuses).
Mark Hamill had to bang his head sixteen times on the ceiling of Yoda's hut before director Irvin Kershner was satisfied with the scene.
George Lucas was so impressed by Frank Oz's performance as Yoda that he spent thousands of dollars on an advertising campaign to try and get him an Oscar nomination for Best Actor in a Supporting Role. Lucas' campaign ultimately failed because it was felt that a puppeteer wasn't an actor. Lucas felt this wasn't fair to Oz, who honestly didn't care.
When shooting on-location in Finse, Norway, a fierce snowstorm hit the hotel where the cast and crew were staying. This would have normally halted filming, but director Irvin Kershner thought these weather conditions were an excellent opportunity to film the scene where Luke wanders through the snow after escaping the Wampa cave. He did this by sending Mark Hamill outside into the cold, while he and the cameraman stayed and filmed inside the hotel's front hall.
Joe Johnston: The director of movies The Rocketeer (1991), Jurassic Park III (2001), Captain America: The First Avenger (2011), and The Nutcracker and the Four Realms (2018) worked on visual and art effects for this movie. He has a cameo as a Rebel in Echo Base before the Rebels evacuate.