“Jack the Giant Slayer” opens Friday at Point, Eastgate, Star Cinema and Cinema Cafe in Stoughton. PG-13, 1:56.

It was just a little over a month ago that “Hansel & Gretel: Witch Hunters” opened, and I joked to a colleague that “Jack and the Beanstalk” would be the next storybook tale to get the IMAX 3D treatment. I thought I was joking, but here it is, “Jack the Giant Slayer.” I would quip that next up will be a PG-13 “Little Miss Muffet,” with Amanda Seyfried battling armies of giant spiders, but I don’t want to give anybody any ideas.

Suffice to say that “Jack” isn’t the worst of the fairytale trend (“Little Miss Riding Hood” owns that) nor is it the best (the gonzo stylish “Snow White and the Huntsman”). But the story of Jack does present a tricky question for director Bryan Singer and his team of writers (including Singer’s “The Usual Suspects” collaborator, Christopher McQuarrie); who’s the movie for, exactly?

You can’t just make a kids’ movie, since the studio is demanding a PG-13 action film that will bring in the teens. But there’s only so dark and violent you can go in a movie that has magic beans as a key plot element. So “Jack,” although energetic and prone to some moments of giddy visual wit, never settles on a consistent tone. It’s too scary for your youngest kid and too silly for your oldest.

A lengthy animated prologue (in which the giants don’t look much different than in the “live-action” film) explains how there’s a world of giants living in the clouds above ours, and how magic beans can build beanstalks to bridge the two worlds, so the giants can come down and kick our asses. (No real upside to the magic beans, methinks.) Luckily, a magic crown is forged that allows the wearer to control the giants.

The human sent the giants upstairs generations ago, but the king’s right-hand man Roderick (a gap-toothed Stanley Tucci) gets his hands on both the beans and the crown, with plans to use the giants to conquer the kingdom. Except farmboy Jack (Nicholas Hoult) gets ahold of the beans, accidentally sprouting a stalk in his living room that sends his house — with princess Isabelle (Eleanor Tomlinson) inside it — shooting up to the heavens.

The king (Ian McShane) sends a few good knights, along with Jack and the sneaky Roderick up to find her. It’s here, I think, that “Jack the Giant Slayer” makes its first major misstep. What I remember of previous fairytale iterations was the tension of Jack sneaking around the giant’s lair, trying not to be discovered, hearing the rumble as the giant gets closer and closer. Here, the humans are caught almost immediately, and the CGI giants are presented almost immediately. Wouldn’t want to waste any of that visual-effects money on actually building a little suspense.

And, honestly, the giants are a little boring. Visually and personality-wise, it’s hard to tell them apart, aside from one that looks like Harvey Keitel for some reason, and another that looks like either Kid or Play from “House Party” (I can never remember which is which.) Otherwise, they’re basically just one-dimensional brutes that like to munch humans like they were at Buffalo Wild Wings.

There’s one clever action sequence, in which gallant knight Elmont (Ewan McGregor) has to avoid being baked into the giant equivalent of a Hot Pocket. But Singer otherwise doesn’t get much mileage out of his villains — other than their size, they’re just generic “Lord of the Rings”-knockoff bad guys. Just imagine the mischief that a more daring filmmaker like Terry Gilliam would have had with this story.

But then, the studio likely couldn’t have trusted Gilliam to hit all the expected notes of big-budget fantasy-action, including the obligatory endless battle between humans and giants. It’s not awful, but for a movie about 40-foot behemoths, “Jack the Giant Slayer” has pretty small aspirations.