“The Rum Diary,” playing in theaters this week, is entertaining enough for movie goers but falls short of fans’ expectations of accurately or satisfactorily representing the Hunter Thompson novel on which it is based.

Directed by Bruce Robinson and starring Johnny Depp, Aaron Eckhart and Amber Heard, the movie’s major redeeming quality is Depp’s acting.

Depp plays journalist Paul Kemp in “The Rum Diary” just as well as he played Raoul Duke in “Fear and Loathing in Las Vegas,” another film based on a Thompson novel under the same name, although both characters are thinly veiled stand-ins for Thompson himself.

Depp gets the character spot on, which is expected considering he was a close friend of Thompson, spent time living in the writer’s basement to prepare for his role in “Fear and Loathing” and financed Thompson’s elaborate funeral.

Besides Depp’s accurate portrayal, the movie veers drastically from the original plotline of the novel, going so far as to completely cut out a main character who played a pivotal role in the central conflict of the story. The ending is also different, with characters missing, roles reversed, and important plot events completely left out.

It is difficult to review Eckhart’s acting in this movie if you’ve read the book, as he essentially plays a conflation of two characters, going by the name of Sanderson but also playing the role of the character Yeamon from the novel.

While it is understandable that these decisions would be made for the sake of making the story more viewer-friendly, there should have been more considerations regarding the target audience.

Set in Puerto Rico 50 years ago, with a storyline revolving around the antics of a drunken, degenerate gringo journalist, it seems obvious that this movie would mostly appeal to a cult audience who would care about accurately representing the novel on which it was based.

Of course, the novel “The Rum Diary” is no “Fear and Loathing in Las Vegas.” Written in the early sixties but not published until 1998, it represents a glimpse into the mind of Thompson as a young, unrefined writer.

In one telling line from the movie, Kemp says, “I’ve got no voice. I don’t know how to write like me.” This line seemed like it was pandering to Thompson fans, pleading with them to excuse the drastic deviations from the original story for entertainment’s sake.

Even if Robinson made the movie a bit grittier and less appealing to the uninformed viewer, a more accurate portrayal probably wouldn’t hurt box office sales, which have been dismal so far anyway, and it would’ve been much more satisfying for those who feel that movies based on books should try to stick to the script.