Nicholas Hoult is a bloodless Englishman and Eleanor Tomlinson the princess he loves in ”Jack the Giant Slayer.” (Photo by Daniel Smith)

Much like the imaginary setting of “Jack the Giant Slayer” — a floating land called Gantua, situated halfway between heaven and Earth, and populated by a race of CGI giants — the fairy tale-inspired film is stuck between two extremes. Too scary for very young children, yet too silly for most older fans of director Bryan Singer’s earlier forays into the Superman and X-Men franchises, “Jack” seems designed to appeal to a very narrow, and possibly illusory, demographic: the mature moppet.

Loosely based on the English folk tale about a boy who discovers a magic beanstalk that leads to the realm of an evil giant, the film includes scenes of pitched battle that resemble outtakes from one of the “Lord of the Rings” films, as well as the kind of belching-and-flatulence humor popular with preschoolers. Although it centers on an unlikely love story — between an adolescent farm boy named Jack (Nicholas Hoult) and a beautiful princess named Isabelle (Eleanor Tomlinson) — the central relationship is as sexless as a prepubescent peck on the cheek.

Couple that with man-eating giants, and the question seems obvious: Who exactly is this movie for?

It’s certainly made well enough. The digitally animated giants, whose kidnapping of Isabelle leads to a rescue mission by Jack, the dashing palace guard Elmont (Ewan McGregor) and Isabelle’s betrothed (Stanley Tucci), are actually kind of cool, albeit in a cartoonish way. Inexplicably, one of them (voiced by Bill Nighy) has a second head sprouting from the side of his neck, like a Gollum-shaped goiter. Voiced by John Kassir, the appendage doesn’t talk so much as roll its eyes, grunt and mug for the camera, in an annoyingly intrusive form of comic relief.

Oddly, the movie isn’t quite scary enough — for anyone older than, say, 10 — to really need it.

In the title role, Hoult comes across as a somewhat zombie-ish leading man, a result of either his limited acting ability or his recent starring turn as an undead teen in “Warm Bodies.” Tomlinson, for her part, is suitably feisty, although in a generic, Disney-princess sort of way. Tucci hams it up nicely as Isabelle’s duplicitous fiance, Roderick, a megalomaniac in tights with a medieval Jheri curl who wants to rule over the giants.

This leaves McGregor as the film’s only actual grown-up hero. Unfortunately, the part that’s written for him (by Darren Lemke, Christopher McQuarrie and Dan Studney) doesn’t live up to the actor’s considerable talent, charm and screen presence. I would much rather have seen “Elmont the Giant Slayer.” But then again, unlike Jack — who looks like a digitally aged version of the baby-faced kid Hoult played in “About a Boy” — I’m old enough to shave.

There are a couple of nifty, if less than jaw-dropping, special effects. But the whole thing never feels entirely — I don’t know — real. Why, for example, are all the giants dudes? Where are all the lady giants, or the giant babies?

It may seem crazy to apply logic to a fairy tale. But isn’t that why kids love them in the first place, because they could be, just possibly, true?


PG-13. At area theaters. Contains bloodless but intense fantasy violence and brief crude language. 117 minutes.