In the latest edition of Gamasutra's long-running game design series, 'The Designer's Notebook,' regular columnist and veteran game designer Ernest Adams introduces and explains Ken Perlin's Law, which dictates that "The cost of an event in an interactive story should be directly proportional to its improbability."
The following extract serves as an introduction to Adams' explanation of this fundamental game design law:
"For a long time now, we game designers have assumed that player freedom is a good thing, especially in the context of fictitious game worlds where the player can move around and explore. This assumption goes all the way back to the original text-based adventure game, Adventure (or Colossal Cave). Adventure was different from other computer games of its day because it didn’t print a list of commands for the player to choose from. Instead, it simply put a prompt on the screen and said, “type anything you want to.” It pretended that you could do anything.
Of course, after five minutes of play you realized that this was an illusion; the game didn’t really understand that many commands. But, among those of us who are optimistic about the potential of computer games, it created a fond hope, a utopian dream: Someday we will create a game in which you can do anything! And this dream has been at the back of game designers’ minds from that day to this."
You can read the full Gamasutra feature
, including modern visions of player freedom, and the theory of "credibility budget" (no registration required, please feel free to link to this feature from external websites).