The narrative follows Ender's journey through military training both on Earth and off world. Chapters begin with a dialogue between two observers to Ender's condition. While intriguing, these characters are not really developed and only demonstrate that there are greater forces on Ender's life than he can comprehend.
Halfway through Card's military science fiction novel, I wondered if the impending alien invasion was even a possibility. When the story finally resolved, it felt hollow and preachy.
I was surprised that Common Sense Media recommends Ender's Game for middle school readers. The language and brutal conflicts are at times disturbing. A thought provoking story for older readers, the character conflicts reminded me of Lord of the Flies. There was minor sexual content as the recruits do occasionally appear nude sleeping and showering (the boys and girls share sleeping quarters) but since almost all the characters are prepubescent, there is no real romance or sex. At least it's not on Ender's mind.
Accelerated Reader lists the book at a 5.5 ATOS Book Level and worth 16 AR Points. Thankfully AR recommends the book for Upper Grades (9-12). Ender's Game has also been made into a movie, but I have not seen it yet. I generally enjoyed the book, but wondered at times if the plot would ever resolve as the military continues to string Ender along, always asking more with nothing to show for it. The book is self contained but leaves plenty of room for the followup novels, of which I have no desire to read.