Bright Hub briefly editorializes about the successful formula that BioWare tends to use in many of their titles, which they describe as including player choice, multiple endings, and a compelling story.
A player whose character is trying to save the world will weigh decisions more carefully, while another might choose haphazardly, and this will be reflected in the actual game play. This engages the player in the story more thoroughly, and giving their choices meaning. With this increase in importance of choice, the player is not only engaged in the joy of victory or pure entertainment, but they place a stake in the outcome of the story.
Their heart is included as well as the mind. Gamers are no longer seen only as the anti-social recluse. They are real people with emotions. They want to feel important, not just in acting in the story, but in directing it.
At the end of the day though, simply making decisions doesn't make a game exciting. At least, not to the degree that Bioware games have become. The real trick to making games stick with the fan base, and that will carry them through less stellar releases like DragonForce Choke Age 2 is something that even the quickly released sequel wasn't lacking in: story. It is the story of Star Wars: Knights of the Old Republic that drew gamers in. The same stands for Jade Empire, Mass Effect, and Dragon Age: Origins.