This movie was fine. It's no masterpiece, but I actually found it much more enjoyable than "The Martian," the vaunted 2015 Matt Damon vehicle. That may be somewhat more scientifically accurate - although it still had its share of errors - but it just used people as setpieces for the situation, with no real character development.
I liked Asa Butterfield as the eponymous character in "Ender's Game," and he's just as good here. Before you tag me as an Asa fan, I didn't like him in Scorsese's "Hugo." Here, he was convincing as a Mars-born child with his childlike, guileless naiveté and tall, gangly build. One professional critic compared this with "Flight of the Navigator," but Gardner isn't the smartmouth kid like David was in that movie, and Asa is a far, far better actor than Joey Cramer was. Likewise Gary Oldman, some of whose roles I have detested (his Doctor Smith in the awful "Lost in Space") while others like his Commissioner Gordon in Nolan's Batman movies were fine. The critics think he was over the top as billionaire mogul Nathaniel Shepard, but I found him to be a rather plausible mix of Steve Jobs' salesmanship, Elon Musk's arrogance and spaceflight ambitions, and Howard Hughes' fascination with flying and reclusive eccentricity.
You can tell that many of the movie's fiercest critics here have their own agendas, usually trying to prove they're smarter than the writer. All their comments do is reveal their closed minds and often their ignorance. One smart aleck claims Gardner's mother looked 5 months pregnant in the film. The shot where she peers out of the spacecraft window as she cradles her expanding belly was at an indeterminate time sometime after her sonogram two months after launch, possibly right before landing more than seven months after launch. Same person talks about Mars gravity being 2/3rd of Earth's. No, it's 1/3rd. Plus she complains that the Earth's resources are said to be depleted. That phrase was Nathaniel reading from a letter he wrote to the President as a 12-year-old, full of youthful enthusiasm and exaggeration, not stated as actual scientific fact. Another critic tries to look intelligent by saying Mars is four light minutes away. It is at its closest, but the distance isn't constant and is over 22 light minutes at its furthest. (Another genius here claims it's 90 light minutes each way.) The communication with Mars was instantaneous because they clearly plastered "QuantumCom light minute compression" on the comm screens to imply they've figured out how to use quantum entanglement for instant data transfer at interplanetary distances (still inplausible as it's based on a common misconception, but still far less fantastical than laser swords, warp drive, time travel, telepathy, teleportation devices or humanoid aliens attacking to steal our water, oxygen, etc.). Besides, it's a dramatic technique, as waiting minutes between messages with no realtime interaction just isn't very interesting, unless you liked "You've Got Mail." Another critic who claims to be an MD rated the movie 1 star for no other reason than they pronounced a test "TROponin" rather than "tropPOnin" as he preferred, even though the former is in fact the correct pronunciation, as any medical dictionary can confirm. I wouldn't want him as my doctor, or even playing one on TV. One complained that Gardner's mother was too young to be a mission commander, but probably never said the same about the similarly young Jessica Chastain in "The Martian." Another smart guy claimed the spacecraft would have accelerated halfway to Mars, providing gravity all the way, then turned around and decelerated. Anybody with a knowledge of physics would laugh him out of the room after telling him that would require several times more reaction mass (fuel) than the total mass of the entire spacecraft, a physical impossibility. One critic savages the movie for having contemporary products in it. It's a relatively low budget science fiction film, not a $400 million blockbuster. They spent their budget on more important things like CGI effects, spacecraft props, Mars sets and weightlessness effects, not wasting it creating an entire future Earth, and the projections in movies set in the near future like "2001" always turn out looking dated after a few years anyway. You get the idea; the criticisms are generally incredibly petty, nitpicky and often just plain wrong. I can see plenty of scientific and technological mistakes, especially the Dream Chaser spacecraft used at the end, which would need a large booster and a launchpad rather than taking off using its own small rocket engines from a runway. But I accept that this is a movie, not a documentary, and focus on the characters, whom I did like and care about.
Basically, the critiques boil down to "it's for kids!" As someone approaching retirement age, I'd much rather be young at heart than cranky and old in the head.
