“The Dark Tower” is widely considered to be Stephen King’s masterpiece, but its mind-bending plot and intricate special effects have delayed its transition to the big screen.

Sony is banking that fans of the series of adventure novels will turn out in force this summer, helping the dark fantasy break through at the crowded summer box office. “The Dark Tower” stars Idris Elba as Roland Deschain, a gunslinger on a mission, and Matthew McConaughey as the Man in Black, a mysterious sorcerer. Newcomer Tom Taylor plays an 11-year-old named Jake who dreams about an alternate universe, and discovers a portal to another world.

On Monday, the studio gave theater owners at CinemaCon a sneak peek at the epic battles and elaborate standoffs in store when the film opens on July 28. It was the first time audiences have gotten a look at a project that’s been shrouded in secrecy.

There were plenty of slo-motion shootouts, including one in which McConaughey’s character catches a bullet in his fingers while his back is turned to Elba.

“You’re trying to save the world, but you can’t even save yourself,” McConaughey taunts Elba, promising that the titular tower will crumble.

“They say what happens in one world echoes in others,” Elba’s character mutters.

One particularly crowd-pleasing moment saw Elba’s character use his augmented sense of hearing to identify where a creepy-looking assailant is and to save Taylor’s character with a well-placed shot that ricochets off of a house and takes down the bad guy from several yards away.

There have been previous efforts to bring “The Dark Tower” to the big screen, with filmmakers such as J.J. Abrams and Ron Howard circling the project at various points. However, they have been canceled over budget concerns or for artistic reasons. This time, the producers think they’ve cracked the code.

In interviews that accompanied the preview, the filmmakers enthused about bringing King’s world to life, with producer Akiva Goldsman calling it the writer’s “magnum opus.” Sony distribution chief Rory Bruer said that “The Dark Tower” has links to the rest of King’s oeuvre, a group of best-sellers that includes “It” and “Salem’s Lot.”

There may have been a nod to those connections in the footage that screened at CinemaCon. Jake is telling his psychiatrist about his visions and there’s a quick shot of a photograph that appears to show an elaborate mountain resort. It’s a dead ringer for the Overlook Hotel, the creepy retreat where Jack Torrance slowly went insane in King’s classic novel “The Shining.”