“Killers of the Flower Moon” is an epic Western crime drama from the legendary Martin Scorsese. Based on David Grann’s nonfiction book of the same name, the story follows a string of murders of the Osage people in Oklahoma after oil is discovered on their land in the 1920s. The film stars Leonardo DiCaprio (“The Revenant”), Robert De Niro (“Raging Bull”) and Lily Gladstone (“Certain Women”).

Scorsese is one of the most acclaimed filmmakers of all time, and every time I watch one of his films, I’m quickly reminded why. While there are many entries in his filmography that I haven’t yet seen, everything I’ve seen has wowed me, and “Flower Moon” is no exception. It’s an exhausting film to watch, especially in a theatrical setting, but the screenplay, performances, editing and directing make the gargantuan runtime of three and a half hours worth it in the end.

One of the most interesting aspects of the film is the story, especially due to how extensively it was reworked. The script, written by Scorsese and Eric Roth (“Forrest Gump”), started as an investigative film about the FBI, much like the book.

However, DiCaprio asked for an extensive overhaul, changing the focus from Agent Tom White to Ernest Burkhart, the nephew of the corrupt cattle rancher William King Hale, and his twisted romance with a wealthy Osage woman named Mollie.

Usually, actors suggesting massive story changes like this leads to disastrous results; as talented as DiCaprio is as a performer, he isn’t a writer or a director. However, the change in perspective made for a significantly more interesting and emotional story, and it also gave the actors a lot more freedom to experiment with their characters.

Lily Gladstone’s performance as Mollie Burkhart is by far one of the best of the year, and she’s a very easy pick for the Academy Award for Best Lead Actress. She truly is the film’s emotional centerpiece, which wasn’t the case in the original script. Thanks to the rewrites, Gladstone has a more significant role in the story, and she was given the opportunity to demonstrate her acting ability … and she ran with it.

De Niro delivers an unsurprisingly terrific performance as lead antagonist William King Hale. He truly embodies an evil, greedy mobster while also pretending to be a friendly benefactor of sorts. It always feels like he’s about to snap into a fit of violence while hiding behind the cuddly demeanor of a grandfather.

I also loved DiCaprio’s lead performance as Ernest Burkhart. He was initially cast as FBI agent Tom White, but he stated that he wanted to play the morally gray Burkhart instead of a clean-cut hero, which led to the film’s extensive rewrites and change in focus. Thankfully, he plays the character pretty well. We can see that Ernest truly loves Mollie, but it’s also important to note how cowardly he is and how complicit he is in the murders of the Osage people. It’s a nuanced character, and he plays it pretty well.

All of Rodrigo Prieto’s cinematography beautifully captures the setting of early 1900s Oklahoma, and the terrific production design lends even more authenticity to it. The score from the late Robbie Robertson, to whom the film is dedicated, makes the revisionist-Western feel of “Flower Moon”even more apparent. Scorsese’s vision for this film was very clear, and he got everything he needed from his collaborators. Not only that, but he spent a lot of time with the Osage people in Oklahoma to get their story right and make sure he was as respectful as humanly possible.

There is, however, one element of the film that I still have mixed feelings about: the runtime. I can’t think of areas where Scorsese could have trimmed it down, but I found the experience of watching this in theaters pretty exhausting because of both the length and the heavy subject matter. If anything, I’d advocate more for a brief intermission in the middle, giving audience members some time to recover before finishing the movie. If films of this length were more willing to have intermissions, I think that audience members may be more inclined to spend this much time in a theater.

Overall, “Killers of the Flower Moon” is one of the most powerful movies I have seen in a long time. Even though the runtime may divide audiences, I still think that Scorsese’s latest is a movie from a master filmmaker at the top of his game.

RATING: 9/10