What makes the Giant's Drink hard to play?

The "mind game" that is introduced in this chapter is another of the games bordering on reality. While it is just a game, Ender remains engrossed in and almost obsessed with it and the need to beat it. It is not clear that the game ever ends, however; the computer can always add new scenarios. The Giant's Drink, at least in Ender's case, is designed so that he only can win by breaking the rules--he has to refuse to drink the Giant's Drink but instead attack his eye. The first time Ender broke the rules in such a "game" was against Stilson, when he chose not to follow the "rules of combat" and kicked Stilson when he was down. We will see, later on, that whenever Ender grows desperate, he breaks the everyday rules in order to win.