Successfully complete the game with any rank under the normal or hard difficulty settings. Start a new game. A Closet Key will appear in your inventory. Use it to unlock the closet in the room where the Hunting Gun was first found to access new costumes for Rebecca and Billy.
Completion bonuses:
Successfully complete the game with a "B", "C", or "D" rank to unlock the Leech Hunter mini-game.
Successfully complete the game with a time between 3:31 and 5:00 for an "A" rank to unlock the Submachine Gun and Leech Hunter mini-game.
Successfully complete the game with a time of 3:30 or faster for an "S" rank to unlock the Rocket Launcher, Submachine gun, and Leech Hunter mini-game.
Note: To a rank after completing the game it must be played under the normal difficulty setting. You will not get ranked under the easy difficulty setting, but can still unlock the Leech Hunter mini-game.
Hint: One hit kills:
When playing as either Rebecca or Billy and you get bit by a zombie, move the character opposite of your main character directly behind the one you are controlling to have him or her shoot the zombie in the head and kill it in one hit, while the zombie deals you no damage. Note: You must have pistol equipped to save ammunition for a one bullet kill.
Hint: Extra inventory slot:
When playing as Billy with Rebecca as the alternate character, have Billy hold all the pistol ammunition for both characters and keep her gun fully loaded. This gives you one free inventory slot.
Hint: Dail door number puzzle:
Enter "4863" on Disc 2, where the cable car is located.
Hint: Chess puzzle:
Look at the smaller chess board on the desk in front of the big one. Arrange the big pieces the same way. The difference is the only white piece by itself. Use Billy to push it down, to the right, and finally right in front of the black piece. The desk will now open.
Information in this section was contributed by Chico and Bella.
Hint: Brake system puzzle:
The main code is 9 + 9 + 9 + 9 + 9 + 9 + 9 + 9 + 7 + 2 = 81. This should activate the brakes for the train.
Information in this section was contributed by RoTTeN.
The second code for the brakes is 7 + 7 + 7 + 7 + 7 + 7 + 7 + 7 + 5 + 6. This will start the brakes.
Hint: Fountain circle puzzle:
When you get to the fountain circle with the six animal statues on Disc 1, use Billy to light the statues in the following order: Deer, Wolf, Horse, Lion, Snake, Eagle.
Hint: Pause timed puzzles:
Try to change to your partner during a timed puzzle. Remain idle at the error message to give yourself more time to study the puzzle.
Hint: Piano room:
When you get to the piano room, make sure you have both characters with you. Have Billy play piano. A door will open by the bar. Have Rebecca go in and take the battery. The door will close. Have Billy play piano again and the door will open.