While they’ve always been interactive, video games began
as very narrative forms of entertainment. After an initial cut scene, setting the stage for the game, you’d receive your first orders and set off on your first mission. From there, you’d be instructed to do something else – and the cycle would continue until you reached the end of the game.
Storylines are still a core part of titles, of course, but more and more, developers are letting you explore the worlds they create when and how you want – letting you roam at will, performing non-essential missions that boost your enjoyment of the game and extend your playable hours.
Read more at Yahoo! Games