Successfully complete the game to unlock the "Enhanced Mode" option, which allows powered-up weapons and more items.
Go to the "Visitor's Bureau" between the Asylum and the Jail. Knock down one of the pieces of fence surrounding the building. Walk or jump onto it. Then, in the direction you would like to move, "kick" the ground. Kicking the ground (in that direction) moves the fence toward the area ahead of you. Because you are standing on it, you are also moving with it. This can be difficult to do at first.
Postal 2: Hints (English)©