In Fatman, the latest film by brothers Ian and Eshom Nelms, Santa Claus is a gruff, defeated man with a drinking problem. Persecuted by those he wants to bring joy to, he at one point suffers a wound in his side. When we meet him, he's venting some anger by shooting tin cans in his back yard. If any Christmas picture screams out for today's Mel Gibson, this is the one.

Yet despite this casting and the increasingly head-spinning plot – the US government hires Santa's workforce to make parts for fighter jets; a rich kid who gets coal under the tree hires a hitman to punish the once-jolly gift-giver – Fatman doesn't elicit the response one rightly expects, the mouth-agape astonishment of wondering how and why such a movie came to exist. The film realises it's being outrageous, but it's not one of those prefab cult movies that cynically throws one absurdity after another onscreen in the hopes of going viral.

This Chris Cringle's despondency comes from the lousy state of the world's children. As he sees it, the naughty population is ever-growing, while the number of kids who deserve the gifts they wish for decreases by the day. Unfortunately, the money his operation brings in – a subsidy check from the US government – is proportionate not to his costs, but to the number of presents he delivers.

As a result, Santa's workshop is behind on its bills and at risk of closing down. Things are so desperate he's finally willing to sign a contract with the Army, militarising his North Pole compound in the downtime between bouts of present-making.

Meanwhile, spoiled Billy Wenan (Chance Hurstfield) rules over his family's mansion while a neglectful father vacations around the world with one girlfriend or another. He's a little tyrant with an amusingly grown-up demeanor, treating maids like his secretaries and taking a cutthroat approach to competition at the Science Fair.

Outraged at the coal he receives Christmas morning, Billy contacts a hitman credited as the Skinny Man (Walton Goggins). The oddly sentimental killer has spent his life hating Santa for not giving him the gifts he wanted decades ago. He eagerly agrees to find his North Pole lair and kill him.

As it moves toward a climax that will require Santa to connect with his inner action hero, the film works better than it should without being as enjoyable as its predecessor, the brothers' much less ambitious Small Town Crime.