The Dark Tower. Good movie in its own right, especially if you like Idris Elba.

First, they took 8 Stephen King books, some of which were like 2" thick, and decided to turn it into a 90-minute PG-13 film. A single film.

Second, because the racist element was so offensive (a Black woman taken out of the 1970s, who has personally experienced racism toward her, is taken to a foreign world, an alternate reality, where she basically is led by an old white man (modeled after Clint Eastwood) and naturally she feels a certain type of way about that) they decided they were going to change it up. Make her white, and him Black. Hence casting Idris Elba as a guy based on Clint Eastwood. Then they dropped her character entirely. I will argue that Elba made a hell of a Gunslinger, but the reason they cast him was because they wanted to turn the whole racism plot on its head. For no good reason. It was fine in the books (this would be The Drawing of the Three, and The Waste Lands, the second and third books).

But for all that, it was an entertaining action flick with a bunch of Stephen King references. I quite like it. As a reader of the books and a fan of Stephen King, I shouldn't, but the movie itself was good.

Honestly that the movie exists at all is the worst change, though.