~2.5 
 You know what? I didn't like this book as a kid and I liked it even less as an adult. 
 The typical response to this opinion is that I need to read the rest of the series before passing judgement. But you know what? I plan on judging this book on the merits of this book, not on the rest of the series--nor on the author's more recent antics. So if you love this book, please go ahead and dismiss my opinion as worthless. This isn't a book where I really want to debate and defend my opinions. 
 I think, at the core, it's because I'm not and have never been the target audience. How can I tell? Well, passages like the following were a bit of a clue: "All boys?" 
 "A few girls. They often don't pass the tests to get in. Too many centuries of evolution are working against them." Scifi doesn't tend to have much of a place for women except as damsels, victims, and tools. In Ender's Game, they fall into the latter two categories. There are two named female characters in the book. Count'em. Two. One is there to be manipulated. The other is there as the Token Female who relies mostly upon informed abilities but is the first to crack under the pressure. (view spoiler)[Sure, we're told she's good--as long as she can be a stereotyped sideshow. She flies into a rage when defeated, then sulks. She's brilliant, so long as Ender is with her. But without the help of a man, she panics. And in the final, most important moments, who cracks first? The weak woman, of course. Petra follows the perfect pattern of the Token Female: she's allowed to be impressive as long as it doesn't matter, but when the real climax comes, she breaks and is sidelined. 
 Much of what made her a good commander was lost. Ender couldn't use her anymore, except in routine, closely supervised assignments. She was no fool. She knew what had happened. But she also knew that Ender had no choice, and told him so. 
 The fact remained that she had broken, and she was far from being the weakest of his squad leaders.And yet who broke? (hide spoiler)] Did this bother me as a kid? Probably not as much as it does as an adult. But every time I reread the books from my childhood, I rediscover the relentless voices telling me that my gender doesn't belong in science or scifi as anything other than tools and victims. 
 And then there's the whole genius protagonist thing. I've always believed that superintelligent protagonists are a mistake because they require rather a lot of the author. Card, however, came up with an extremely clever workaround: Ender's story is interspersed with various military leaders commenting on what a genius he is. This is, in my opinion, an utterly brilliant gimmick. Take, for example, the "Giant's Drink" subplot. In the video game he plays obsessively, Ender gets stuck on a puzzle where a giant offers him two drinks, one of which is poison. He plays over and over and over and picks the wrong one again and again and again. And then, in a rage, he attacks the giant, which strikes me as a pretty standard thing to try. But fortunately, our observers were there to tell me that rather than exhibiting a fit of childish pique or trying a natural tactic in a videogame, Ender had been brilliant: "Isn't it nice that Ender can do the impossible? ... What matters is that he won the game that couldn't be won." The whole book is like that. I was continually amazed by the simple strategies that the observers insisted on labeling as pure genius. 
 Even so, I think the book's exploration of preemptive attacks and overwhelming force adds an interesting dimension to it all. Most of the book reads like a recapitulation of Heinlein's Starship Troopers. Again and again, Card reinforces the idea that it is laudable to retaliate with extreme force against those who use extreme force, and against those who attack first, and against those who might be a threat. But at some point, ambiguity creeps in. And no, that's not to say that the book's message is a pure repudiation of preemptive attacks. The most fascinating thing about the story to me is that Card doesn't really try to turn it into an aesop. (view spoiler)[Let's take it as read that Genocide Is Wrong. But Ender is using the same tactics he used throughout the book. So where did his actions become wrong? When he changed the rules to win the game? When he murdered a classmate in the bathroom? When he stamped a would-be bully's face in the ground? Sure, it's easy to say that all of Ender's tactics were wrong, that using a disproportionate amount of force to "end things" is simply inherently wrong. But I'm not sure that this is what the book is saying. So, then. At what point does overwhelming force become inherently wrong? (hide spoiler)] No matter how Ender's Game looks at the outset, it's not just a repetition of Starship Troopers, and that's certainly something.