Roald Dahl weaves strange yarns for kids, mixing imagination and whimsy with a distinct strand of menace. The enduring popularity of his stories—Charlie and the Chocolate Factory was published in 1964!—depends on all those threads, menace included. What good is Matilda without the criminally neglectful parents or abusive Agatha Trunchbull? Or James and the Giant Peach without the cruel aunts? Or Charlie and the Great Glass Elevator without the Vermicious Knids?
The thing is, children love books that harbor cartoonishly-rendered dangers which nonetheless ring true with their own fears: bad adults, bad choices, bad space aliens. Dahl's books, like Lewis Carroll's Alice books, need that sinister edge to balance out their (sometimes literal) sugary content. It's what keeps it interesting—without the possibility of danger, the playful loses its punch a bit. G.K. Chesterton wrote about how fairy stories need “dragons.” And kids get this intuitively.
But sometimes adults don't. The result might look a bit like Steven Spielberg's The BFG: utterly harmless and totally sweet-natured, visually sophisticated and imaginative but narratively closer to Teletubbies than its source material—which is to say that if you're over the age of four, it's pretty dull.
In truth, that's not a total condemnation; there's surely a place in our world for children's entertainment that only appeals to children. Mark Rylance, fresh off his Oscar win, is great as the BFG, and Ruby Barnhill is a fetching Sophie, along with an all-star cast (Penelope Wilton, Jermaine Clement, Rebecca Hall, Bill Hader). The screenplay is by the late Melissa Mathison, best known for writing E.T. the Extra-Terrestrial. But this is The BFG, and it's directed by Spielberg, and it lives in a universe where Pixar has rewritten the book on what makes for a good theatrical release for the whole family, and that universe demands slightly more than a bedtime story designed to lull you to sleep.
The BFG tells the story of Sophie, a girl living in an orphanage run by a typically Dahlian crab named Mrs. Clonkers (who barely appears in the film). One night she sees a giant down the street, travels with him to his home, and discovers that he is a Big Friendly Giant, hence the name, who spends his nights blowing dreams into children's bedrooms. To put it in Pixar terms, he's Sulley, and she is Boo.
The other giants are Big (even Bigger), but not at all Friendly, and this is the first real clue that the film has gone awry a bit. In the book these giants are terrifying and subsist on humans, and here are their names: The Fleshlumpeater, The Manhugger, The Butcher Boy, The Meatdripper, The Childchewer, The Bloodbottler, The Maidmasher, The Gizzardgulper, and The Bonecruncher (who pulverizes two humans per night for dinner). They're decimating the population of children around the world. In the film, though they're big and sort of scary, they're mostly just dumb louts, and the menace seems to have been dialed down to the bare minimum to keep the plot coherent. Certainly you can (and probably need to) tone down the gristle factor on screen. Books have the advantage of leaving the visualization of villains to the reader's imagination; the individual reader's mind then can moderate the threat, according to what it's capable of.