JACK THE GIANT SLAYER "Jack the Vine Climber" didn't have quite the same ring to it.

I AM ENTIRELY in favor of the current trend of reframing familiar fairy tales as big budget, bludgeoning blockbusters. So what if it still hasn't been done very well? That's scarcely the point—these movies contain monsters, swords, magic, and knights in armor. My inner child goes a long way to forgiving the shortcomings of these loud, usually thoughtless films—and while Bryan Singer's loud, thoughtless Jack the Giant Slayer has many shortcomings indeed, I'm more or less okay with them. Mostly.

The film mashes up two semi-related fairy tales, "Jack the Giant Killer" and the more familiar "Jack and the Beanstalk," with a whole bunch of Hollywood hokum; the result is about 80 percent too much plot. I'll try to keep this brief: Poor farm boy Jack (Nicholas Hoult) is pressured into trading his horse for some beans by a monk, because the monk... okay, I forget what the monk was all about, but the beans turn into a beanstalk, and somehow a princess (Eleanor Tomlinson) ends up at the top of the beanstalk, which I couldn't explain to you if I tried. So the king (a sadly wasted Ian McShane) sends his two best knights (Ewan McGregor and Eddie Marsan) to climb it, and for reasons I can't be bothered to remember, the evil Lord Roderick (Stanley Tucci) goes up with them—and of course, Jack does, too.

You will not be surprised to learn that a whole bunch of nasty, ugly giants live at the top of the beanstalk, nor will you be surprised that the rest of the movie details, in strangely inconsistent CGI, the lengthy battle between giants and men. Parts of the movie are breathtakingly rendered; other parts look weirdly shoddy. But the most distressing thing about Jack the Giant Slayer is how many missed opportunities there are. (For example, Bill Nighy is the voice of the giants' leader and he has two heads—comedy gold, right? The script has neither head say or do a single interesting thing.)

Jack the Giant Slayer alternates between long, plodding stretches of tedium and a few fun, breathless passages. Naturally, McGregor is far and away the best thing here, cheerfully playing up the Errol Flynn-style swashbuckling absurdity of his surroundings. But the movie mostly clunks along with the gracelessness of the thick, dumb giant army. Still, like I said: swords. Magic. Monsters. Knights in armor.