If we often think that a movie doesn't need to have sequels, this case is the opposite: this movie should have been thought of as the beginning of a franchise of several movies.
As far as I could tell, after some reading, this work of cinema was based on a work by Stephen King, composed of a long series of books. I'm sure the source material is good, King is one of the best and most ingenious fantastic writers of our time and his vast literary oeuvre has already made for surprising and remarkable films. What I question is the way this adaptation was made: what are eight books converted into a two-hour film? They probably only took advantage of a handful of characters and locations and threw everything else in the trash. Works like these can only be adapted in the form of trilogies, tetralogies or, in the television market, as series. Otherwise, the source material is not properly exploited in its richness.
Regardless of these issues, the film is moderately good: it all starts when the young protagonist, haunted by visions he has, finds a portal to a world he does not know, the world of his visions, and finds a Gunslinger who will help him. Deep down, he already knows the essential: the universal balance is in danger because an evil sorcerer wants to bring down the grandiose Dark Tower which, at the center of all things, harmonizes this balance and cosmic energies. I am explaining it simply and in my own words. Now the task of the two heroes is to prevent this from happening.
The best thing about this film is really the feeling of adventure, risk, the almost constant action and the way everything unfolds quickly, without dead moments. As an entertainment film, it is very good, and if we forget that it is the worst adaptation of King ever made for the cinema, we can really have a good time watching it. The big problem here is how rushed everything feels, with the film trying to do too much without having to reach its two and a half hour runtime.
The quality of the cast is another asset that makes the film work reasonably well. None of the actors are amazing, there are no great performances, but what was done is enough to push the film in the right direction: Idris Elba is charismatic and likable without ceasing to be fearsome, something his character demanded and which the actor knew to adapt. Tom Taylor also did a good job in the role of the young hero, a role where it would have been very easy to make mistakes, be superficial or ham. The villain has fallen into the shoes of Matthew McConaughey, and despite being suitably dark, he's not really a palpable threat.
Technically, the film relies heavily on CGI and effects. The film called for that, given the plot and sci-fi theme. The CGI and effects are good and work well for the most part, although there are a number of options and solutions that I would consider debatable. For example, the film never explores – nor does it have time for – the connections between parallel universes, and how there are so many people in our world who know this. The film would have gained in quality if it had been given an additional hour, or if it had been thought of as the beginning of a broader franchise, with several sequels. The cinematography is very good, the filming work is average, it has good sets, good costumes and excellent action scenes. The soundtrack, I confess, is not convincing, but it works effectively, which is already positive.