This is almost a pretty good book about the ethics of boot camp, but I have two problems with it that just totally break the whole thing for me.

First, Ender has been selected for super-soldier training because he's supposedly a genius. But a five-year-old human, no matter how intelligent, shouldn't have emotions and concerns and physical development belonging to a teenager. It's so hard to repeatedly ignore this anachronism when it's forced so frequently. Everything would have been just fine if the author made him oh maybe eleven instead of five. Or if the author gave him some other inhuman trait to show that he was a mutant. Like if he always had to wear a helmet to protect his gigantic cranium. That would have been fine.

Second, the story was unfortunately written before the invention of the Real-Time Strategy game. The author couldn't have predicted how underwhelming his description of the most advanced war simulators of the future would sound to an average kid playing the games of the year 2000. We now know that many of Ender's feats don't require genius to perform, just a lot of Mountain Dew.

In other words, the author bent too many common-knowledge truths to be believable, although perhaps they weren't common knowledge at the time. It's just unfortunate in retrospect.

On a side note, it's a bit telling of the times that Ender spends a lot of time playing this fantasy scenario exploration game having more in common with games of the 1980s than with today's tropes.