The Big Picture: ET The Extra-Terrestrial

Do you believe in magic?

Can it really be 20 years ago? Watching ET The Extra-Terrestrial for the first time since 1982 is to be reminded not only of time's confounding perspectives but of the enduring impression a "classic" movie can leave upon us. That so much of ET, its shape and light and texture, seems completely familiar is no tribute to the retentive force of my memory but to the magical fluency and precision of Steven Spielberg's film-making, a sureness of touch that carries you along so irresistibly that the experience has the hypnotic enthralment of a spell.

Twenty years on, it bewitches still. This anniversary reissue has been given a digital spring-clean and furnished with three or four new scenes, but it's substantially the same picture: this is no Apocalypse Now Redux, with its 50 minutes of previously unseen footage and additional characters to load what was already an overcrowded boat.

Spielberg hasn't turned ET into the big deal of a "director's cut" because he has the confidence of an artist who got it right the first time; why gild a lily as pure and fresh as this? That confidence is right there from the opening minutes of the film, in which Spielberg, without resorting to dialogue, sets up the plot in a sequence of images – a spaceship abandoning a dark wood, an alien that gets left behind, a human search party bristling with flashlights. Spielberg has called ET his most personal film, and in the story of Elliott, a lonely 10-year-old boy who's befriended by an otherworldly visitor, one can discern certain aspects of the director's own childhood: after his parents separated, the teenage Steven and his three younger sisters were raised by his mother in a happy suburban home. Spielberg was apparently recreating the remembered cosiness of those early years, of the nerdy boy obsessed with science fiction and the latest gizmos, and his instinctive empathy with children is evident in the absolute rightness of his young cast. Henry Thomas as Elliott is an earnest, solemn-faced kid who knows that his mom is hurting but feels powerless to help her; he has the slightly quizzical melancholy of Charlie Brown, and the squat, bulbous alien he tempts into friendship with a trail of sweets turns out to be his Snoopy.

On the film's release Spielberg explained, in an interview with Martin Amis, how he had relied on his instinct: "If you over-rehearse kids, you get a bad case of the cutes. We shot ET chronologically, with plenty of improvisation. I let the kids feel their way into the scenes." That refusal to over-rehearse might be a lesson to any director who works with children: too often we see a movie collapse into winsomeness – or "a bad case of the cutes" – because child actors seem to be reciting rather than speaking their lines. The spontaneity has been drilled out of them – see, for example, Harry Potter and the Philosopher's Stone.

Thomas never overplays, and nor does Drew Barrymore as his six-year-old sister Gertie, who treats ET with the tenderness and respect she'd normally reserve for a favourite dolly. Even better is Robert MacNaughton as Michael, their older teenage brother; his look of saucer-eyed amazement on being introduced to Elliott's secret new friend is a reaction shot right up there with Sigourney Weaver and co on seeing that less cuddly extra-terrestrial burst out of John Hurt's stomach in Alien. These three performances are simply vital to the film's mood, which maintains a delicate balance between yearning and dread, between the dream of transcendence and the knowledge that it can't last.

It's a surprise to be reminded that this very personal, intimate film wasn't actually written by Spielberg but by Melissa Mathison, who is wise enough to temper the sense of wonder (a Spielbergian crux) with a bracing dose of domestic slapstick. One of the new scenes involves Elliott having to feign the heaves down the phone in order to rescue ET from drowning in the bathtub, a joky prefigurement of the later scene when the creature lies apparently dead beneath the windowed coffin, and Elliott's breath frosts over the glass.

Sometimes the wonder and the slapstick are so closely entwined you can't tell them apart. The telepathic union between boy and creature is played out in the lovely crosscutting between ET drinking his first beer in the kitchen and Elliott getting drunk in his school biology class: looking at a frog trapped beneath glass Elliott is reminded of ET, and launches a frog jailbreak in the laboratory. In the chaos he also manages to kiss a girl who's a good six inches taller than him.

The film contends that adults, mostly shot from behind at waist level, have been dulled to that feeling of wonder. When Elliott's harassed mom (Dee Wallace) is packing the fridge she's too preoccupied to notice ET, even when he's standing right in front of her. Only Peter Coyote as a federal space agent senses what this strange visitation might mean to a child, and by that stage ET has been hunted down and quarantined inside an acreage of plastic curtains.

So what exactly does ET stand for? Though infinitely wise and ancient, he has no urgent message for the world; indeed, he's here by default, having missed his ride home. Having previously thrilled cinemagoers with monstrous apparitions in Duel and Jaws and in the same year as ET produced Poltergeist, Spielberg may simply have wanted to suggest that creatures from the unknown weren't necessarily hostile.

ET delivers on the promise of the benign otherworldliness Spielberg first posited in Close Encounters of the Third Kind, though his principal role is less a messenger from beyond than an answer to a bereft kid's prayers. Elliott's home remains broken but his heart gets healed; by the end, both he and ET are ready to "move on". Their parting, a vision of hope that's also a farewell to childhood, nutshells the affective power of this remarkable film. Once again, hankies at the ready.