...and make sure to include parodies of that Call of Duty mission and massacre of Akella some random Russian publishing company.
Here's an example story:
Postal Dude joins neonazi movement that wants revenge for Hitler's death. Their goal is to kill all Russian people. Massacre of black people and Jews is optional, but recommended. Every time Dude kills Russian, he earns respect points which allow to increase rank and unlock abilities such as being able to call for backup, Russian people detector (like one in P2), etc. Also, Dude gets access to weapons and cash. Eventually Dude earns the rank of fuhrer and proclaims whatever city he is in free from immigrant scum. Obviously, this happen at fourth of July, which leads to a great celebration. Dude is proclaimed national hero for his feats in keeping America's integrity. After that Dude announces that he will be running for president. He creates new party called National Socialist American Workers' Party with the motto "We are 99%" which quickly spreads through social networks and gives him unanimous support. As a result, he easily beats unnamed black president in votes. During inauguration ceremony he says that America is finally free from disease in it's upper corridors of power. That White House was named like that with clear intentions that Americans seem to forget. Dude acknowledges that evil comes from the outside and says that "SOPA is for pussies" and declares that he will bring democracy to the whole planet, whether it wants it or not. And then everyone lived happily ever after. Except those who don't live in America. F**king commies.
THE END.