Successfully complete the game on the easy, normal, and hard puzzle difficulty settings. Select the hard puzzle difficulty again and begin a new game to have a new combination of puzzles.

Successfully complete the game. Start another game and enter the extra options menu to access new features.

A "Bullet Adjust" option can be set, allowing the normal amount of ammunition found at a location to be doubled or tripled.

A "Noise Effect" option can be toggled.

Another new option can be toggled, allowing scenes to be viewed without distortion.

Successfully complete the game on the normal difficulty and normal puzzle difficulty settings. Start a new game to find a chain saw among logs before the cemetery.

Unlock all five endings, then start a new game. All signs will now be revealed.

When you get almost to the end of the hospital area and go down in the elevator, you will get a call on the radio. It is game show which will ask three questions. You must go to the third floor storeroom to get your prize. The combination to the box is 3 1 3.

There is a hang man puzzle in the labyrinth area. You must pull down the top left rope, then return to the room with the hanging men. The top left one will be gone. In his place will be a key and a note.

Successfully complete the game two times. Start a new game to find the Hyper Spray on the south side of the motor home.

In the first battle, equip your rifle and as soon as you get the chance, shoot him four times. He will run away. Follow him into the next room. Get far away from him and just keep shooting until he dies. If he gets in close, run away and shoot him. If done correctly, he should be locked in between shots and you will not get hit.