The only reason I bring up the book/movie comparison in this review is because the reasons why The Martian falters are that it fails to truly capture the spirit of the novel.
For such a vast frontier (dubbed the final one by many), it can be difficult to produce a meaningful space flick that doesn't disappear on the dark side of cinematic giants like Interstellar and Gravity (which this reviewer has admittedly yet to see). In comes The Martian with Matt Damon and Jessica Chastain (off of previous space movies) and director Ridley Scott who decided to helm this movie instead of a Prometheus sequel.
Matt Damon plays Mark Watney, NASA astronaut and botanist who is accidentally marooned on the red planet after a freak storm chases the rest of his crew, who believes him dead, off the planet. What transpires is a sort of Man vs. Wild: Mars Edition as Watney figures out exactly how to survive on a desolated planet until help can retrieve him.
The Martian is pretty much summed up by Watney's assertion in the trailer "I'm going to have to science the shit out of this." What works for The Martian is the humor conveyed by the statement as well as the scientific aspect of the movie. Unfortunately, the film scales back on both aspects from the book. What The Martian fails to convey is the amount of brain power Watney puts into all of his calculations, the immense risk at every step he faces, and the endless drudgery it requires. Often the movie minimizes hours and hours of labor into a montage. We don't get a good sense of how demoralizing his situation would be to the average man and how crucial his spirit is as well as his mental determination. I'm not certain the movie allowed us to be truly concerned for Watney's well-being at any point in the movie, which seems foolish since he's marooned on Mars, for goodness sake.
Ridley Scott is no stranger to space. He gave us the psychologic horror film claustrophobic vibe with Alien. He gave us the visually stunning, (arguably) thought-provoking Prometheus. So it's puzzling that the visuals and the mental scope of The Martian appear so flat. Admittedly, The Martian is a different space horse. However, considering the planet is the main antagonist of the story, it should require more brutality or stark isolation cinematically. Watney's main conflicts arise from the planet: how to survive physically and mentally. He's alone, and the film doesn't allow us to feel that desolation as much as it could.
When reading the book, we get a sense of exactly why Scott chose the cast he did. But due to ineffective writing or execution, what mostly happens is a star-studded cast not doing much to stand out, like an ineffectual Soderbergh movie. Damon might be the exception to the rule as it's great to see him loosen up and have fun in a role. He does as much as possible to bring the warmth of Watney's personality to the fore and it drives the movie as much as the science does. In directing Apollo 13, Ron Howard said he chose Tom Hanks for the main role because the actor embodied the everyman that the audience would instinctively want to bring back home. The Martian works because Damon is able to also be that man that we want to see home.
These are all truly small flaws though in what is really an enjoyable movie. What is there not to like about watching Matt Damon rove around on Mars' surface to disco music? It would be more appropriately released among summer popcorn fare, but it's not a displeasure to enjoy in the theaters before the serious Oscar contenders come out to play. Given Scott's oeuvre, it would be worthwhile to see a happy medium between Prometheus and The Martian: a space movie that doesn't take itself too seriously, but dazzles us visually, but in the meantime it's great to see something a bit lighter from both Scott and Damon.