Excluding the last move of the game, if the effect of an action on the end of the game is known with certainty, there will be no tension in it. If the player perceives no effect of his unique strategy and preferences, he will feel no better than a machine tirelessly stamping out the perfect choices.

Calculated Risk is an useful way to add tension to a game. Players weigh the odds, and decide either to risk losses for possible gains, or play it safe and keep what they have.

This principle was encountered while trying to create a NonPlayerCharacter? mechanism for a BoardGame prototype. Instead of secretly drawing a card, a player, at the end of his turn, would choose one of the NPCs and flip over the top card of the pile. The NPC would perform the specified action (many times detrimental to the players) and then the player would take the card into his hand. The player could continue doing this as many times as he felt comfortable doing so. This particular comfort level might vary from player to player, but it always made card drawing an exciting time. (It also made for a rather long TimeBetweenTurns, so the mechanism was eventually dropped.)

This rule is likely at the heart of Gambling? games. Even though any mathematician or economist could tell you that the games are fixed to favor the house, huge numbers of people continue to play them. To these people, the chance, however small, of hitting the big Jackpot is worth the chance, however large, of losing money. Many of these people will tell you that this risk is exciting, and even the responsible players consider their loses more like fees for having a good time. That many gambling games, which are quite popular, are almost entirely calculated risk should be sufficient cause to consider the concept.


A good formal overview of some of the principles behind this rule can be found in The Psychology of Choice, (free registration required) by John_Hopson?, at Gamasutra.

Therefore, imbue the MeaningfulChoices of the game with a chance of that they will not have exactly the expected result.