The Dude in the orginal Postal was extremely violent. Often shooting and burning people and making quips about their deaths. It's unknown what he did to anger police, or why he went Postal but the game ends with the dude in a mental asylum.
After the orginal Postal the dude's personality changed. He became cynical and slightly less murderous. After doing various things in the town of Paradise like buying milk, cashing his check, returning his book to the library, praying, and getting napalm the dude ends up in the middle of the apocalypse were cats fall from the sky. He returns home to his hateful wife and tries to end his suffering.
Postal 2: Apocalypse WeekendEdit
After the dude's adventure's during the weekday end he wakes up in the hospital because of a self inflicted head wound. This wound makes him have bizarre hallucinations involving Gary Coleman. Eventually after doing some odd jobs he finds his dog who was at the pound and escapes paradise before the second apocalypse.
Postal 2: Paradise LostEdit
After the second apocalypse the dude crashed his car outside the city and ended up in a coma for over a decade. He set out on a quest to save his dog again. But this time it was from his horrible mutated form. After finishing off his wife he either starts a third apocalypse or becomes the king of Paradise.
It's not canon!