Friday, January 18, 2008

Cause and Effect

Principle: Avoid responding to the player's actions with behavior that is contrary to reasonable player expectations, as it breaks the implied "contract" between the player and the game designer.

Players cannot form a useful mental model of the game world when things happen unexpectedly or without an apparent cause. Players should be able to understand the laws at work in your game's environment, and to make appropriate deductions based on their understanding of those laws.

If unexpected or incongruent behavior is desired, players should ultimately be able, by virtue of the game's design, to reconcile such behavior with their operative mental model of the game world -- which by its nature is allowed to change as the game progresses.

Thursday, January 10, 2008

Meaningful Mistakes

Principle: Sometimes a player's mistakes aren't really mistakes. If a player has no good reason to believe a particular action might lead to failure, then failure should not be blamed on the player.

Failure by surprise occurs when the player's actions do not appear as if they should lead to failure, because the relationship between action and outcome is either obscure or counterintuitive, or because the element that makes a particular action lead to failure is presented too late for the player to react to it. King's Quest and Dragon's Lair are known for this kind of failure mechanism, where the wrong move can easily result in unexpected death or failure1.

A game should generally provide enough clues for players to anticipate danger, and should otherwise give players a fair chance to react to any surprises.


Footnotes

1. See
Ways to Die/Lose in King's Quest and Let's Fail Dragon's Lair v2.0 (not safe for work).

Monday, January 07, 2008

Walkthrough? I Don't Need No Steenking Walkthrough!

Principle: If a game requires a strategy guide or walkthrough to complete, it's broken. If the game may be completed without one but nevertheless provokes a not insignificant number of players to consult one, it's just as broken as before.

Rationale: Completing a game should require no external clues. A player's failure to figure out a particular puzzle without outside help is actually the designer's failure to provide sufficient clues within the game. The game world is missing essential information; the game is broken.

Exceptions: If a game mechanic explicitly involves the application of external information, this principle does not apply.