Tuned (See also: Polished, Tweaked)
A game mechanic can be considered tuned when it correctly constrains the player experience to have the desired effect
The opening four bars of “Smoke on the Water” by Deep Purple are perhaps the best example of the power chord. Nothing screams sex, drugs and rock & roll like these iconic sounds.
Smoke on the Water
But if you play them even a tiny bit incorrectly, you’ll have a discordant mess. Instead of the desired effect (impressing all the girls at the party) you will achieve the exact opposite. In the same way, game mechanics must be precisely tuned to insure they work together to produce the desired experience and prevent undesired ones.
A Fire in the Sky
Unlike balance, which must be considered across the entire community for the life of the game, a game that is tuned for one individual is probably tuned for most players. That is because the tuning process constrains the entire possibility space, not a specific experience. As it eliminates poor experiences and emphasizes or rewards the desired ones, the differences between player skill levels and choices are automatically included.
Balanced (see also: Fairness, Longevity)
A state in which a game can be played indefinitely by its entire community without developer interventions or player conventions.
There is no such thing as a “balanced game”.
This is not to say that there is no such thing as a perfectly balanced game, but that balance is not a quality of a game at all, but of the experience of playing a game. And since this experience depends on who is playing, a game can only be considered “balanced” for a specific group of players.
The latest 2d fighting game might be balanced when you and your friends are taking turns mashing buttons, but degenerate into ridiculous 100+ hit combos when mastered by a some over-zealous Japanese teenager. To be considered truly balanced, a game must go beyond this kind of local balance and be balanced for the entire game community.
Balance is often temporary; Imbalance usually permanent
In a similar way, it’s clear that any game may be balanced for brief periods of time. Often the most balanced point in a multiplayer game’s life-cycle are the first few nights after launch, before the community has discovered the optimal strategies, glitches and cheap tactics, before the unending train of patches and tweaks. So any useful definition of balance must also require the game experience to remain stable for a significant time.
Finally, balance requires a certain amount of independence and permanence. The purpose of balancing a game is to allow players to strategically plan and skillfully execute within an impartial system that they can predict. This does not happen if the game requires constant changes and tweaks, either by direct developer updates or community-endorsed “honor rules”.
Note: This definition of balanced does not require that a game be “fun” to be “balanced”.
Affordance (Also: Usability, Discoverability, Intuitiveness)
The quality of an object or environment that allows a Player to intuitively discern and perform the gameplay action associated with that object or environment.
In his most profound philosophical work Being and Time, Martin Heidegger makes a distinction between two types of attitudes that we can have toward an object. First, an object can be “present-to-hand”, which means that it exists and we can observe it and theorize about it. Heidegger claims that this is an uncomfortable mode for us, that it is inferior to the more natural second attitude where an object has an immediate purpose, which he calls being “ready-to-hand”.
Imagine you are walking through a Home Depot and see a collection of hammers hanging from pegboard in the tool section. Let’s say you are an English major and you have never seen a hammer before. You might assume that you had stumbled into an unusual art gallery and start admiring the variety of colors and shapes the artist had created. Clearly they are a phallic representation of our patriarchal history…
In this example, you would be treating the hammers as if they were “present-at-hand”. In a game, every time the player is forced to stop and think about the possible actions an object affords they are forced out of their flow state. If this happens too often they will never be able to relax and enjoy the game.
Chess - A terrible example of percieved affordance
Now imagine you are in a burning building and the only exit is blocked by a flimsy plywood door. This time when you see the hammer on the wall you do not perceive it as an object, but as a tool with a clear purpose. There is no hesitation because there is no analysis. The hammer is “ready-at-hand” and that door is “ready-to-smash”. There is no break in flow because both the hammer and the exit door have clearly perceived affordances.
This is especially important in games, because the player cannot even begin to play until they understand what actions they can take. The faster they can understand what is possible, the earlier they can get past the theorizing state and into the flow state of proper play.