In a career known for Going Big, Stephen King’s Dark Tower series still stands apart. Beginning as an enigmatic, college-written mash-up between Sergio Leone and J.R.R. Tolkien, it developed over the decades into a gloriously overstuffed, wildly imaginative mix of authorial insertions, ties to King’s other works, and metaphysical hooey. Even when it seems to occasionally forget the main plot (hello, book six), King never stops swinging for the fences.

The long-gestating feature film adaptation is also a mess—but for far less interesting reasons, flattening out the saga’s copious highs and lows into a humdrum, flavorless experience. Yes, it’s unlikely a 95-minute movie could ever capture the gargantuan scope of the source material. But, jeez, couldn’t it at least try?

Drawing seemingly willy-nilly from all of the books, The Dark Tower: The Movie follows a boy (Tom Taylor) plagued by visions of the universe ending. As the Lovecraftian apocalypse looms large, he's drawn into a world-hopping showdown between a weary mystical gunslinger (Idris Elba) and a black-clad agent of chaos (an amusingly pissy Matthew McConaughey).

The good news first: Elba is terrifically right for the part, fully inhabiting King’s laconic badass as soon as he steps in front of the camera. More’s the pity, then, that director Nikolaj Arcel treats him like a supporting character in his own story, minimizing his presence in favor of blurry shoot-outs and inserts of McConaughey commenting on the action from afar.

The critical knives are already out for The Dark Tower, with rumors of reshoots and studio interference flooding the internet. Unfortunately, what’s on screen is really just thoroughly mediocre, with its most potentially interesting elements set aside in favor of a synergistic long game. (At this point, the announced plan for a bunch of sequels and an accompanying TV show seems a tad … optimistic.) If The Dark Tower was a disaster, at least it would be more memorable. recommended