Surely even the notion of 'completion' is the same kind of extrinsic motivation? If the game is intrinsically fun, why have a score, or an end screen, or a fail state?
> If the game is intrinsically fun, why have a score, or an end screen, or a fail state?
The end screens stick around because people really do want them. But it's very common for people to enjoy games without ever seeing an end screen.
The other two examples tend to undermine your point. Fail states have been methodically stripped from games because people hate them. Scores are more neutral; nobody cares one way or the other. But they're disappearing too. (Mostly they've already disappeared.)
You have a score in Super Mario Brothers because arcade games have scores. Arcade games have scores that people care about because the machine displays a high score list that other people will see. But nobody has ever cared about score in Super Mario Brothers - there is no high score list, and if there was one it wouldn't matter because the machine is in your home.
There are "scores" in King's Quest and Return to Zork that track your completion of the game (including optional parts). That is the same function that achievements serve today, except that achievements do it better by allowing you to tell which ones you've completed. Which of three optional two-point events you completed in King's Quest is information you can't extract from a score of "perfect minus four".
