“The Dark Tower” is a competent science-fiction film with several good performances.

The movie is based on the series of eight novels (1998-2012) written by Stephen King that stitches together several cinema genres and literary influences.

In “The Dark Tower” movie, Roland Deschain (Idris Elba), known as the last Gunslinger, is battling Walter O’Dim (Matthew McConaughey), known as the Man in Black. Roland is trying to stop Walter from toppling the Dark Tower, purported to be the energy force that powers the universe.

The movie-goer is brought into this mythical universe through the eyes and mind of Jake Chambers (Tom Taylor, in his theatrical movie debut), whose notebook sketches have images from nightmares he has had, depicting the Gunslinger, the Man in Black and the Dark Tower.

Jake’s mother (Katheryn Winnick) and stepfather (Karl Thaning) think that he has a psychological disorder. The psychiatrist (José Zúñiga) thinks the bad dreams are triggered by Jake’s difficulty in coping with the death of his biological father.

It’s decided to send Jake to a psychiatric clinic. However, Jake suspects clinic officials are what he calls The Skin People, who have scars along their necks that indicate they are in league with The Man In Black.

“The Dark Tower” has its moments as a scary summer movie, but not enough.

Elba is powerful yet sensitive as the Gunslinger. McConaughey is stoically creepy as the Man in Black. Taylor is excellent as the pre-teen.

Effective in supporting roles are Jackie Earle Haley (Sayre, one of the Man in Black’s minions), Dennis Haysbert (Roland’s father), Claudia Kim (Arra, who’s aiding the Gunslinger), and Abbey Lee (Tirana, also on team Man in Black).

Nikolaj Arcel (director, “A Royal Affair,” 2012), directs “The Dark Tower” from a screenplay he co-wrote with Akiva Goldsman (“The Da Vinci Code,” 2006; “I, Robot,” 2004; Oscar screenplay recipient, “A Beautiful Mind,” 2001), Jeff Pinkner (TV’s “Fringe,” “Lost,” “Alias”), and Anders Thomas Jensen (“In A Better World,” 2010; “Love Is All You Need,” 2012).

“The Dark Tower” movie, and seemingly the books, as well, derive themes from the Man With No Name gunslinger character played by Clint Eastwood in the movie, “The Good, The Bad, And The Ugly” (1966); J. R. R. Tolkien’s “The Lord of The Rings” books (beginning in 1954), and “The Matrix” (beginning in 1999) movies. Stephen King has said the “The Dark Tower” book series was inspired by the poem, “Childe Roland to the Dark Tower Came,” by Robert Browning.

“The Dark Tower” is a hybrid of fantasy, science fiction, horror and western movie genres that sometimes works and more often does not. The movie becomes less interesting as it goes along and plays out with a routine science-fiction fantasy battle sequence.

The movie is least successful in its action sequences, which are rendered with predictably over-the-top Computer Generated Imagery (CGI) with quick cuts (fast editing), and fantastical creatures akin to those in the “Alien” (1979) movies. Many scenes are so dark that the creepy creature scare-factor is lost.

The movie is most successful in its Spielbergian scenes of children in peril, scenes where Jake is bullied by fellow school students, scenes with Jake and his parents, and scenes with Jake and Roland, who become a sort of science-fiction version of Huck and Jim from Mark Twain’s “The Adventures Of Huckleberry Finn” novel (1885).

The screenwriters should have returned to scenes emphasizing the rapport between Jake and Roland, and given them moments for further bonding. Instead, Jake and Roland disappear through a science-fiction portal bound, mostly likely, for “The Dark Tower” sequel.

“The Dark Tower,”MPAA rated PG-13 (Parents Strongly Cautioned. Some Material May Be Inappropriate For Children Under 13.) for thematic material including sequences of gun violence and action; Genre: Action, Adventure, Fantasy; Run time: 1 hr., 35 min.; Distributed by Sony-Columbia Pictures.

Credit Readers Anonymous:In a scene early on in “The Dark Tower,” Jake is shown holding a toy model of a red, two-door 1958 Plymouth Fury, aka “Christine” of the novel written by Stephen King and the 1983 theatrical feature movie.

Box Office,Aug. 11: “Annabelle: Creation” scared up $35 million, somewhat reversing the last two lackluster weekends at the box office, as it toppled “The Dark Tower,” which dropped three spots to No. 4, with $7.8 million, $34.3 million, two weeks, with “Dunkirk” staying at No. 2 with $11.4 million, $153.7 million, four weeks, and keeping the offensively-titled animation feature sequel, “The Nut Job 2: Nutty by Nature,” opening way back at No. 4 with a dismal $8.9 million even though it was shown in 4,003 theaters.

5. “The Emoji Movie” dropped two places, $6.6 million, $63.5 million, three weeks.

6. “Girls Trip” stumbled two spots, with $6.5 million, $97.1 million, four weeks.

7. “Spider-Man: Homecoming” slid down one slot, $6.1 million, $306.4 million, six weeks.

8, “Kidnap” dropped three places, opening, $5.2 million, $19.3 million, two weeks.

9. “The Glass Castle,” $4.8 million, one week.

10. “Atomic Blonde” dropped three slots, with $4.5 million, $42.8 million, three weeks.

Unreel,Aug. 18:

“Logan Lucky,”PG-13: Steven Soderbergh directs Katherine Waterston, Daniel Craig, Channing Tatum, and Sebastian Stan in the Comedy Crime Drama. Two brothers try to pull off a heist during a NASCAR race in North Carolina. That’s one way to boost ratings.

“Patti Cake$,”R: Geremy Jasper directs Danielle Macdonald, Bridget Everett, Siddharth Dhananjay, and Mamoudou Athie in the Drama. A New Jersey woman, Patricia Dombrowski, who goes by the stage name, Patti Cake$, wants to be a rapper.

Two Popcorn Boxes out of Five Popcorn Boxes