Get rocket launcher:
Finish the game as Chris or Jill in under 3 hours. After the credits roll, arocket will launch into the air. Save the game to a memory card. Then start a new game using the data off the card. When you check Jill's inventory, there is a new weapon, tha all-powerful rocket launcher. this will destroy zombies, Hunters, and other assorted monsters with one shot.

Change character's clothes:
Finish the game and rescue your 2 other buddies. After the credit sequence, a screen appears that says "You got the special key." Then save the game. Start the game you just saved, and when you go into the hallway with the giant mirror, (you enter this room from the main hallway), you can unlock the door in the back. Now you can change your characters' clothes.