Bethesda has revealed that the upcoming Fallout 3 will have anywhere from nine to twelve different endings, all dependant upon how a player conducts him or herself throughout the course of the game.
Said Bethesda’s Pete Hines, "There will be somewhere between nine to 12 different endings to the game based on what you’ve done in the game. So it’s something that is inherently a diverging path. It may be some of the same things but doing them in very different ways, and ultimately that will define your gameplay experience.
The game will feature fewer quests than the developer’s previous outing, Oblivion, and will allow or restrict access to future tasks based on the choices players make. There will be many different ways to complete the quests in Fallout 3.