Aside from a well-executed third act reveal, "Ender's Game" is a plodding, unmoving sci-fi non-adventure that is only saved by some strong key performances.
This adaptation is a strongly-acted and well-written sci-fi exercise - but it's clunky execution results in some vague story stakes and uneven pacing.
Asa Butterfield and Harrison Ford anchor this boot-camp story with human, precise performances. Butterfield's Ender is vulnerable, ruthless, empathetic and decisive all at once. Ford is sympathetic as a mentor and willing to make any sacrifice as a military man.
These two actors could have easily lost control of their characters and their emotional swings. Their actions in the film's third act are extreme - but they're completely legitimized by the wise, intelligent acting choices of Butterfield and Ford established in the film's first two acts.
Oscar-nominees Abigail Breslin ("Little Miss Sunshine") and Hailee Steinfeld ("True Grit") lead a strong army of young supporting actors. For a cast that is 75 percent young actors playing emotionally pressured children and teens, "Ender's Game" benefits from a stable of young actors who elevate the story.
The peripheral characters are served no favors by their thin roles. The brilliant talents of Viola Davis and Ben Kingsley are wasted on characters who only nudge the overall story, but never affect it in any significant way. Davis and Kinglsey show up and disappear, with their absence leaving little consequence. Some of the bullies who berate Ender border on cartoonish meanies of little dimension or humanity.
The first two-thirds of "Ender's Game" is essentially watching a squad of child soldiers play war games. The film offers no clear stakes of Ender's success or failure in 'Battle School,' except that he has been tapped as the next great commander. The fact that Ender is covertly shepherded along also undermines any narrative stakes and saps dramatic tension from the consequences of his actions.
The result is two film acts that focus on Ender playing strategy-based games - and people watching Ender's progress. And then some people are mean to him. It's only the characterization of Ender that keeps this film afloat for much of its running time.
"Ender's Game" only picks up some amount of energy and excitement in its third act, where characters have been adequately defined, a crisis takes shape and narrative stakes are defined.
A pervasive undercurrent throughout 'Game' questions the ethics of pushing children into military exercises. The unrelenting training clearly affects Ender throughout his journey. Unfortunately, the 'child army' scenario is barely justified in one line that almost occurs in passing. Simply stating that 'children can process more information than old people' in one brief bit of dialogue is the bare minimum required to prop up this entire premise - such a minimal effort ultimately results in minimal story value.
The final resolution - which is clearly sets up sequels - is flat and sort of random. While the film does an adequate job of questioning the ethics of winning a war at any cost, it suddenly fleshes out the alien threat in its closing minutes. This conclusion is unnecessary, forced and ultimately throws cold water on an ending that smartly focuses on Ender's realizations about warfare.
Lastly, "Ender's Game" dangerously flirts with playing in a world accessible only to sci-fi geeks. It establishes a fuzzy history of a vague, ill-explained alien invasion, which (sort of) necessitates an army of children who play war games all day. The film keeps referring back to this fuzzy near-future Earth, where family sizes are regulated and all children aspire to 'Battle School' ... but with almost no good explanation why.
Final verdict: "Ender's Game" is a fine young adult action film - but it fails to realize the full potential of its high-minded themes, instead relying on blatant exposition to force the story forward. Solid acting, great dialogue and impressive visuals save the film's meandering story when it dips into boredom territory ... which happens frequently.