I am writing a game and app version of Doom. I wish to get it to update via web or disk drive. And I want to know how to update it without losing all settings, saved games and other things like that.

So I wish to make it better for the user after I have brought out the game and then add to it. Like an online virus checker, can update its virus database. I wish to update my game, in the same way as such.

How can I do this, quite quickly without much code in doing so?