Ostensibly, Hansel & Gretel: Witch Hunters sits at the nexus of the spate of fairy tale movies we've seen over the last few years and Abraham Lincoln: Vampire Hunter. Take well known historical figure/literary character. Turn him or her in to an extremely campy action figure. Box office profit.
Spiritually, though, it's a direct descendant of The Evil Dead. There's foul language, over-the-top makeup for its creepy-crawlies and comic spurts of blood aplenty. OK, so it might be a whole helluva lot more nonsensical than anything Sam Raimi ever did with the iconic Ash, but there's at least the same joie de vivre. H&G: WH will leave you shaking your head if you spend more than a half-second thinking about the plot or the motivations of its characters (especially its supporting ones), but as you're shaking your head, it will be hard not to simultaneously grin. The lesson here, I suppose, is that if you're going to be an inane piece of crap, do it with enough spunk and people will be forgiving of your many flaws.
Jeremy Renner and Gemma Arterton play the title characters -- survivors of the cannibalistic witch, just as in the fairy tale by the Brothers Grimm, who, now all grown up, hunt witches for a living. The pair are hired by the mayor of Augsburg to track and stop a powerful witch, played by Famke Jannsen, who has been kidnapping children from the town to sacrifice them in a grisly once-in-a-Blood-Moon tradition. There is a troll named Edward, a love interest for Renner and even a Hansel and Gretel fanboy -- all of whom are lightly sketched characters sucked in to the orbit of the two heroes by only the loosest of connections.
These plot details don't really matter because a.) they don't really make any sort of sense, and b.) even if they did, they would still only serve as vehicles for extended action sequences with anachronistic weaponry that are punctuated by extreme gore. I can get behind that conceit. Hell, I loved AL: VH and I own a copy of director Tommy Wirkola's most famous film, Dead Snow, which captures that mood much more nimbly. What really didn't work for me, even beyond the plot, was Renner's failed attempts to channel Bruce Campbell and the not-so-subtle incest-y vibe between him and his co-star. (Seriously, if that was intentional, just run with it next time. The weirder, the better in films like these.)
With a little flesh on this skeleton script, an all-in-or-cash-out decision on whether or not to make it a little freaky between Hansel and Gretel and a leading man with the capability to firmly plant his tongue in his cheek, Hansel & Gretel: Witch Hunters would have felt much less half-baked. As it is, you'll probably need to be half-baked to fully enjoy it.