1UP: You've mentioned that the game will have multiple endings, perhaps as many as a dozen. Without giving away any spoilers, can you explain the sorts of things that will affect which ending the player reaches? For example, will conversations affect the outcome of the game, or is it primarily larger-scale, world-shaking actions?

EP: We went back and forth with the impact of dialogue on the character, and ultimately decided we didn't want to penalize or reward the player for carrying on a conversation. What you say and how you say it will certainly affect how NPCs react to you, and whether or not they'll give you quests, but not the ending of the game. [That] really depends on some of the big decisions you make during the course of the game, as well as your karma. And your karma changes based on your actions. So [if] you destroy Megaton [a city built around a supposedly inert atomic bomb], your karma plummets, so that will certainly affect the ending. But there are other moments too, key moments during the game, that greatly determine which ending you get.