
Fallout 3 is the third installment of the award winning Fallout series taking place in a post apocalyptic future. Everything in the game is more or less inspired by the "atomic age" from Big Boy Bobbleheads to round robot butlers. The player starts the game as a baby choosing his or her S.P.E.C.I.A.L. stats(Strength, Perception, Endurance, Charisma, Intelligence, Agility, and Luck) and how he or she will look, all masked under an ingenious system designed to keep the player immersed in the game. Upon the players completion of character set up a series of events is put in motion starting with the characters father fleeing their safe but oppressive home "Vault 101". The player is forced to look for his father and is free to choose how to do so, attacking enemies in his way, completeing quests for NPCs (Non-Playable Characters), and accumulating the best weapons and gear.

Fables innovative execution of good and evil resulted in players playing through the game multiple times trying to experience the game through both views.
Grand Theft Auto IV took a different approach to how players interact with morality. At certain points within the game the player is forced to choose between killinga character or sparing their life. The game has multiple endings that are determined by which path the player chose to take. GTA IV also presents the player with a choice of getting revenge or dealing with those that have wronged him, also leading to different possible endings. Yet even though there were morality choices in GTA players usually only played the game once because no matter what the player does the only thing he misses out on is a cutscene which he can see online with no real feeling of loss.
Fallout 3 takes a new and unique approach to tackling good vs evil. Players are awarded good and evil karma for not just the actions they take but also how they interact with their environment. Fallout 3's creator did not want the player to be performing random acts of opportunistic evil that would be canceled out by a equal act of good, he wanted it to be more like real life where you are considered good or evil based on all your actions. To this end the players cannot see how "evil" they are or how much "good" they will accumulate for performing certain deeds.
My roomate and I have been playing through Fallout 3 utilizing two very different strategies. I have elected to take the path of the righteous do gooder, helping the inhabitants of the capital wasteland. My roomate on the otherhand is on a path of death and destruction, killing everyone he meets and stealing from the poor and rich alike.
During the course of the game we encountered many towns and locales including one called Megaton which had been built around an ancient atomic bomb reminiscent of Fat Man. The mayor approaches the player with a simple proposition, disarm the bomb for the town and receive a palrtry sum of in game money, caps. A little while later we encounter a mysterious Mr. Burke in the town saloon who offers us much more money and a plush suite in a luxury tower in return for detonating the bomb which would result in the death of all the townspeople. Furthermore Mr. Burke provided all the items you would need in order to blow up the bomb and collect your reward immediately whereas if you wish to save the town you need to wait until you level up quite a bit and raise your science and explosives skills, something that takes hours of gameplay.
The player is thus confronted with a dilemna, destroy the town and reap the rewards quickly or delay gratification and help out the people of Megaton. Playing the part of the messiah I spent hours leveling up my character and collecting the necessary skills before finally completing the quest and collecting my reward which by then seemed inconsequential to my rich character. My roomate immediately destroyed the town and was able to obtain his simmilar reward which helped his low level character immensely.

Later on my roomate and I were in the middle of a mission, escorting a group of scientists to a safe fortress while being chased by evil Enclave soldiers. Halfway through our escape into the seweres one of the scientists suffers a medical emergency and the player is forced to choose between four different possible actions.
The player can convince the others that they should leave the injured scientist as he could slow them down and lead to their capture.
The player can give the injured member 5 stimpacks(items that replenish health) which are fairly hard to come by and creates a significant dent in the players medical inventory.
The player can give the injured member 3 buffouts(items that give a temporary boost to strength at the cost of a bit of health, the in game equivalent of drugs) however these are also semi-rare and can help the player significantly later on.
And finally the player can shoot the injured scientist in cold blood and eliminate the problem. This obviously leads to a loss of karma and confidence from the surviving scientists.
I had in my inventory enough stimpacks to heal him, however I wasn't keen on just giving away my hard earned items for free. Giving out buffouts was a more attractive choice as they cost less than stimpacks and I personally hadn't used them in a while (the reason which I will get into later on), however I only had 2 of the necessary 3 so that wasn't an option. I debated leaving him behind but I felt an obligation for keeping him alive --eliminating the option of killing him as well-- therefore my decision seemed fairly straightforward. I gave him the five stimpacks and kept going, with no reward save a few karma points.
When my roomate encountered the same situation he chuckled a bit, pulled out a .44 magnum, and shot him in the head, execution style, end of story.
One of the best things about these "go anywhere, do anything" games is the amount of creativity it inspires in players. Case in point is the concept of "proxy killing", in order to avoid losing karma and still kill certain NPCs that need to be terminated players have come up with an ingenious solution. Rather than kill the NPCs themselves players will provoke them by targeting them with a non lethal weapon or punch them barehanded turning them hostile. Once the NPC becomes hostile you are allowed to defend yourself and kill them in self defense.

Games like Fallout 3, Fable, and GTA IV, all understand that allowing the player to make his or her own decisions is an integral part of creating a truly immersive and captivating game. Players can indulge in their fantasies of destruction and revenge and become the most ruthless villains yet in the end even the most cold hearted will pause and reconsider his path.