Influence in Games. Games can be thought of as systems and the player should be considered part of that system. Often, the player is represented literally, through an avatar, but other times the player acts more like a god, influencing the game world from above with no physical representation within it. In either case, it's a fundamental rule of game design that the game acknowledge the influence of the player. Influence can vary from actions causing reactions all the way to actions causing permanent reconstruction of the game world.
Persistent influence has evolved from early examples like Pac-Man, where the player gradually cleared the board of dots, to today where, in many modern shooters, the players can literally tear down the environments around them.
Modern RPGs, such as the Elder Scrolls series, strive to go even further and create "living" worlds where decisions follow the player through the game. Taken to this extreme, influence seems to be in opposition to the goal of impulse; persistence means players can't act impulsively and without consequence.
But there is a benefit to actions having lasting effects; as decisions carry greater weight, the fantasy becomes more immersive. The fictional world feels more real. Influence enables one type of fun at the expense of another.
God games take the most extreme approach, and embrace influence as more than just a source of realism: as a source of entertainment in itself. The player is no longer a simple actor who must deal with the consequences of his decisions. The player is a god, free to decide the lasting fate of others.
In games like Civilization, Black & White, or SimCity, the player has complete freedom to steer the fate of a society without fear of direct consequence. Sure, there are explicit objectives to these games, but for many, they take a secondary role to the freedom of choice and influence. As a child, I can still remember discovering I was in the minority of my peers in that I played SimCity primarily to build cities and not destroy them.
Morality in games. Up until recently, games paid very little attention to morality. Conventions like killing enemies by the thousands, invading NPCs' homes without thought and destroying furniture in the search for cash and power-ups are evidence of this legacy.
But as video games have become richer experiences and greater depth has been instilled into their worlds, they have come much closer to modeling our real world. As the resemblance gets closer, it becomes easier to project the morals of our real world onto the game world.
Many modern games have embraced this convergence, introducing simple morality or karma systems into gameplay. In these systems, certain actions increase karma, others decrease it, and the result is the player is labeled as either "good" or "evil". More often than not, the karma system is also tied to the unlocking of features, and the choice runs the risk of becoming more tactical than moral.
For a decision to be truly moral, the tactical results of the two options should be difficult to compare. For example, "evil" provides wealth, while "good" provides reputation, and translating between the two is an inexact science.
Mass Effect 2 does a good job of isolating morality in choice by building morally ambiguous scenarios and then asking the player to arbitrate. The dilemmas involve significant story investment yet carry little actual gameplay relevance (at least that the player is able to predict while making the choices).
In a different example, Modern Warfare 2 has a controversial airport massacre scene, "No Russian", where the user is asked to fire into a crowd of innocents. Whether the player chose to contribute or simply fire into the air makes no real difference to the progress of the game, but probably leaves a lasting impression in the mind of the player nonetheless.
Morality is not limited to realistic video games. A game need only evoke parallels to real-world moral choices to be effective. Brenda Brathwaite's widely cited experimental board game Train was able to pose moral tension through simple toy trains and wooden pawns.
The objective of the game was to cram as many pawns into your boxcar as possible and move it to the end of the track. The moral difficulties arose from the aesthetic elements, which not-so-subtly invited players to imagine themselves as German officers tasked with transporting people to concentration camps.
Because morals are inherently personal, it's advisable to approach them objectively. Rather than force subjective "good" and "evil" labels on players, provide opportunities to draw parallels to real-world moral dilemmas (for example to sacrifice an individual for the good of many) and then give your players the freedom to choose without persuasion. If the moral choice is too clearly one-sided, tactical incentives could be added to "balance" the choice and encourage players to weigh morals as part of a larger equation.
Individuals are daily faced with conflicting demands. Selfish demands to acquire resources and leave a lasting legacy and moral demands to respect others. This balancing act of constant compromise rarely gives individuals the opportunity to indulge either side to satisfaction. Games offer a virtual environment where players have the opportunity to play with power, influence and responsibility in a context where they have the freedom to explore choices reality does not afford.
For this vicarious experience to be effective, the game environment must be able to accurately model the real-world choices. In non-games, where modeling an entire world is probably not feasible, the focus will most likely need to be narrow and explicitly designed.