In order to develop a useful understanding of a system, one must know how the system works internally, at the lowest level. Even an exhaustive memorization of every stimulus and response associated with that system is weak compared to an understanding of the underlying elements that cause a system to respond the way it does. One must fully understand the smaller elements that make up the system and how they interact before one can fully predict the overlying system. This is why chemists try to understand how atoms interact, instead of just listing what happens when you mix various chemicals. The designer of videogames needs to understand gaming in the same way.

In this article I'll attempt to break down and expose one of the key elements that exists at the lowest level of most good videogame experiences. It is useful to break down our understanding of videogame fun to the most basic level because if we can achieve that, we gain a simpler, more generalized understanding of video gaming that transcends boundaries between genres or styles. Principles that apply at the lowest level aren't confined to a genre. Thus, what made Half-Life fun was the same thing that made Bejeweled fun, which was also the same thing that made Starcraft fun. These games may seem totally different in play style, complexity, and theme, but all three were popular and very similar in one of the most fundamental aspects of interactive games. That is, they all presented the player with a continuous stream of difficult and interesting decisions.

Decisions are ultimately what make a game. The only thing that separates gaming from books, movies, plays, and music is the element of decision-making. None of these traditional entertainment forms afford the entertainee any capacity to make a decision about anything. Books, plays and movies are still unarguably superior to games in their ability to tell complex, interesting stories. Few videogames could even be reasonably argued to have come close to a good movie or book in terms of character development, plot and thematic development. In terms of visual eye candy, movies still blow videogames out of the water because of the power of prerendering, hand-optimized shot-by-shot composition, and custom-chosen viewing angles. The question becomes, if games are so inferior in story, and visuals, then why does anyone bother playing them?

There are several answers to this question, but I'm going to focus on one. The ace that gaming has up its sleeve is that it gives the player opportunities to make decisions and then observe the results of those choices in a consequence-free zone. This is why people play videogames instead of watching movies. Almost all good games do this very well.

Often people will mistakenly believe that the concept of decision only includes big, branching storyline-type choices, like those that appear at branching story paths. Not so. The important decision making in videogames occurs extremely frequently and is concerned with relatively small changes to the game world. Decisions like whether to reload a weapon or instead wait another one second to re-evaluate the situation are what should concern game designers.

Analysis of the best decision-making games reveals some interesting correlations between game fun and the type of decisions presented to the player. These correlations are:

1. More difficult decisions are more fun.
2. Decisions that have the most significant and tangible effects are more fun.

Let's look at these two in detail.

Aspects of Good Gameplay Decisions

1. Difficult Decisions

	Starcraft

It should be obvious that decision-making isn't the only thing that makes game fun. Games can and do still have stories or eye candy that provide an element of entertainment. In order to analyze decision-making gameplay free of intellectual interference from other sources of fun, we'll look at a group of games which include the least amount of these other factors. Multiplayer competitive games typically have no story, and some of the most popular ones are ugly enough to make a small child cry. These traits make them excellent subjects for decision/fun analysis.

Multiplayer real time strategy games in particular are excellent examples. At all times, the player must decide what his spending priorities are, where to focus his attention, how many resources to put into scouting, defense, offense, economic development, and so on. RTS games provide the player with a constant stream of difficult and interesting decisions by ensuring that the player must be constantly compromising. Each decision always offers at least two strongly competing options, which makes it difficult, and thus, interesting. Many decision points present far more than two possible options, which make them even more challenging.

A common example of this type of excellent decision is one which all RTS players make thousands of time per game: what should I look at next? Common possible options include:

1. Any group of my resource gatherers
2. Any one of my defensive lines
3. Any one of the battles which is currently running
4. Any enemy base
5. Any part of my production line

Very frequently many of these options are vying strongly for attention, which makes this a very difficult choice. A player may be micromanaging a battle, but his economy will be dying from lack of attention. If he leaves the battle, however, his troops will be at a disadvantage and vulnerable, but then again, his better stewardship of his economy may allow him to better reinforce his army, or to fight another battle another day. The simple decisions as to whether to check one's base is one that will be influenced by too many factors to list here. At high levels of play, good attention management becomes as much a skill as anything else. The richness and temporal density of the stream of decisions presented to the player is what has made RTS games so popular.

Multi-player first-person shooter games like Counter-Strike are also excellent examples of decision-making gameplay. Like RTS games, they offer the player a continuous series of difficult decisions, and each decision has many equally-weighted sides. Common decisions include the following:

1. Should I reload now or later? What if the enemy comes around the corner while I'm reloading? But what if I run out of ammo while I'm fighting an enemy?
2. Should I move my position forwards, backwards, laterally, or not at all now? What if I get shot while I'm in between cover? But what if I lose because I don't make my objective? But what if I get killed because I'm too far out front of my team? But what if the team mates covering the other entrance are killed and I get shot in the back?
3. Should I buy a weapon now? What if I run out of money when I need it later? But what if I die this round because I'm unarmed?

The specific circumstances of each individual match make every instance of these decisions unique. This uniqueness of every decision is what makes these games fun over the long term. Uniqueness is a sub-property of difficult decisions. In order for a decision to be difficult, it must be sufficiently unique. Each decision cannot have been made before; otherwise it is no longer a decision. If you present the player with exactly the same situation over and over, he will learn what the best thing to do is and thus the choice becomes easy. Easy choices are not really choices at all, any more than presenting an FPS player with a cliff edge is a decision point. The decision not to jump is a rather easy one, and thus not a decision at all.

Decisions must be unique to be difficult. The beauty of multiplayer games is that they can present millions of possible situations because there are so many possible interactions and situations between human players, and because human begins have so many unique, individual traits that make each opponent different. Interactions between multiple players add exponentially more complexity to the situation.

So, in order for a decision to be fun, it must be difficult, and in order to be difficult it must also be unique.

2. Tangible and Obvious Results

The process of designing a decision opportunity is not all a designer needs to do. The aftermath of a decision-making event is important as well. A player's enjoyment of a game can be enhanced greatly by the amount and type of feedback that they receive from the game as a result of their decisions. This is why impressive explosion, gunfire and blood effects are important in FPS games, or why good puzzle games often include flashy effects to mark important events. Seeing an enemy die spectacularly is a reward for a decision well made, as is hearing the trumpet call at the end of a puzzle game well won.

	Bejeweled

Each decision can thus be evaluated not only on its difficulty and uniqueness, but by the power of the feedback that results from it. The same difficult, unique choice can be gratifying and interesting, or rather pedestrian based on the strength and tangibility of the feedback it produces.

There are many ways of delivering feedback to the player: visual, auditory, narrative, constructive, and so on. Some simple examples of feedback are the flashy effects that appear in puzzle games when the player makes points, the blood sprays in FPS games (though there is also a strong element of role-playing here), the accumulation of wealth or valuable items or character traits, the forward movement of a story or formation of an alliance, and so on. Feedback design is a well-developed and generally well-understood field of game design.

Multiplayer games, interestingly, have an inherent advantage when it comes to rewarding a player's good decision. When someone else is on the other end of the line, winning a conflict comes with automatic positive feedback. Defeating a real live human being in any kind of contest, even anonymously over the internet, is a reward in itself. Good feelings associated with beating human opponents are a well-developed part of human biology. This, in addition to the uniqueness of human opponents, is one of the things that have made multiplayer gaming so compelling.