The trailer: Few films in recent years have endured a more troubled production process than Jack the Giant Slayer, an ambitious 3D fantasy/comedy that reimagines the classic fable of Jack and the Beanstalk. (The film has been in production for nearly three years, and was originally scheduled for a splashy summer release in June 2012. Instead it will come out in March 2013.) Now, finally, the first full-length trailer is out, giving most fans their first real look at the movie. And "if you think you know the story, you don't know Jack," proclaims the surprisingly light-hearted trailer, which emphasizes the film's extensive special effects and comedic supporting turns by Ewan McGregor and Stanley Tucci. Check it out:

The reaction: "We don't know what to do with Jack the Giant Slayer," says Meredith Woerner at io9. This trailer is "shooting for fun and epic," but coming off as "strangely silly" instead. Well, silly isn't a bad thing, argues Brendon Connelly at Bleeding Cool. Evoking the whimsical humor of previous fantasy comedies like The Princess Bride and Stardust, "this trailer seems to do a fine job of showing us what world we're in." Fantasy comedies aren't for everyone, says Zach Dionne at Vulture. But fans of the genre will likely be thrilled by this latest glimpse of Jack the Giant Slayer.