Based on Orson Scott Card's 1985 novel of the same name, "Ender's Game" is set in the future, after the Formics, an insect-like alien species, have attacked Earth. The population was decimated because Earth wasn't prepared for the assault. In anticipation of the next invasion, the smartest children are trained in advanced computer simulations, history, and rigorous exercises. The idea is that children incorporate and process information much faster than adults, so they would be better suited for the battle against the Formics.

The movie focuses on 12-year-old Andrew "Ender" Wiggins (Asa Butterfield), the youngest child in the family. His brother Peter (Jimmy Pinchak) and his sister Valentine (Abigail Breslin) "washed out" of Battle School because he was too aggressive and violent, and she was too kind-hearted. Ender is the middle ground between his two siblings' extremes. He's smart and very strategic, but he's also shy and sympathetic.

Colonel Hyrum Graff (Harrison Ford) sees military genius in Ender's words and actions and invites him to Battle School. Before long, Ender wins the respect of his teammates and easily masters the difficult battle scenarios. It's important that they work well together because they're preparing for battles that will determine the fate of humanity.

The plot has been streamlined to focus on Ender's preparation for war against the Formics, making it better suited for a movie audience. While this made the story less political, the remaining material still contains plenty of political stances.

The book also handles the battles differently, which increases its emotional impact. It's not as if the movie is all rainbows and unicorns, but it's an important distinction. (It also needs to remain vague so we stay spoiler-free.)

The children are portrayed as slightly older than they were in the book. Kids graduated from Battle School at 12, which is Ender's age in the movie, but he's younger than his fellow classmates. Of course, there's no "right" age at which you can be ready to bear such an enormous responsibility.  You just have to be "ready enough," to quote Graff.

While the plot is enticing enough to reel you in, the movie's visuals will keep you mesmerized.  It's a huge relief that prior movie adaptations hadn't been attempted because the technology to convincingly display the battle scenarios has only become available in the past few years. (No repeats of "WarGames" or "Hackers," please.) It's a pity this film isn't available in 3-D because that would've been a real treat.

All of the acting is spot-on. Ford is great as the gruff colonel, and Ben Kingsley affects a convincing New Zealand accent as Mazer Rackham, a Maori soldier. If there's a weak spot, it's that Breslin (Little Miss Sunshine has grown up!) is underutilized. She has a one-note performance as the concerned, nurturing sister, and that's all she's asked to do. It would've been great to see her role expanded and made as complex as it was in the novel. There is also an entire cast of talented teenage actors who were unknown to me prior to this movie, but I wouldn't be surprised to see them cropping up in future film projects.

It's 16-year-old Butterfield who steals the show, though. He puts in an amazing performance, whether he's standing his ground against bullies, showing his vulnerability at being the new kid in school, commanding his squad in battle, or weeping at a great atrocity.

Even if you're not a sci-fi fan, "Ender's Game" is an excellent way to spend two hours. Take away the sci-fi angle, and you have a story about struggling against insurmountable odds and stepping up when duty calls. The visuals are stunning, and the acting is solid. It may not be as substantial as the book, but it is a commendable adaptation.

Score: 8.0/10

"Ender's Game" is rated PG-13 and has a running time of 1 hour and 54 minutes. It is being shown in 2-D and IMAX.