What is the climax of this novel? What happens? How do the events of this novel make you feel?

The climax of the novel was when Ender thought he was being put to the test with a 'final exam', to see if he was worthy of being the ultimate leader. Little did he know that what he had done all this time, fighting on the simulator, was actually real. The 'final exam' was in fact the last battle of the third invasion, and despite the fact that passing the final exam was not his main concern, he successfully killed all the remaining buggers and won the war. He was shocked when he found out that what he had done was real, not just a game, and the killed the buggers without being aware of it. Everyone then praised him and he became a hero, but Ender doesn't feel the same. I was quite surprised at this myself, as I thought this was just a preparation, and I wouldn't have been able to predict it. But it does make sense and surprising as it was, I am glad for it.