Despite being over 10 years old, this game still ranks as one of the most involving and atmospheric experiences ever created. Even today the freedom, creativity and ability shown by this game has rarely been beaten and is one of those few games where you could play it several times over and still not experience everything the game has to offer.
It is rare to find a game which makes you think about the consequences of your actions. It is rarer to find a game that makes you think about the sort of character that makes those actions. But then there's Fallout. Fallout makes you think about the person controlling the character in the first place.