Most of the full-body puppetry was performed by a 2'10" tall stuntman, but the scenes in the kitchen were done using a 12-year-old boy who was born without legs but was an expert on walking on his hands.
The end of the film was one of the most significant musical experiences for composer John Williams. After several attempts were made to match the score to the film, Steven Spielberg took the film off the screen and encouraged Williams to conduct the orchestra the way he would at a concert. He did, and Spielberg slightly re-edited the film to match the music, which is unusual since normally the music would be edited to match the film (though Spielberg and Williams previously used this method for Rencontres du troisième type (1977)). The result was Williams winning the 1982 Academy Award for Best Original Score. He recreated this at his last appearance with the L.A. Philharmonic at the Hollywood Bowl in 2013, conducting the orchestra live while the last reel was shown on the jumbotrons.
Steven Spielberg shot most of the film from the eye-level of a child to further connect with Elliott and E.T.
At one point, Gertie looks down at E.T. and says, "I don't like his feet." This was ad-libbed by Drew Barrymore and was actually her referring to the grouping of wires coming out of the E.T. puppet. She also ad-libbed the line, "Give me a break!" after Elliott tells her only little kids can see E.T.
Lord Richard Attenborough later said he felt bad that his own movie, Gandhi (1982), beat this movie to the Best Picture Academy Award because he considered his friend Steven Spielberg's movie more deserving of the award and was convinced before the ceremony that it would win. Attenborough described E.T. as "a quite extraordinary piece of cinema."
Steven Spielberg: [separated parents] Elliot's parents are divorced, and it's implied that his father wants nothing to do with his family. Divorce and absent fathers are common tropes in Spielberg's films.
Steven Spielberg: [fathers] Elliott, Michael, and Gertie lost their father and look upon E.T. as a father figure.