Successfully complete the game on any difficulty to unlock Doctor mode.
Successfully complete the game to unlock the Nightmare difficulty.
FAMAS with infinite ammunition:
Successfully complete the game on the Nightmare difficulty to unlock the FAMAS with unlimited ammunition.
Successfully complete the game with the fourth ending to unlock the Hidden Package.
Successfully complete Doctor mode to unlock nightvision.
Successfully complete the indicated task to unlock the corresponding item:
Camera : Successfully complete the game in under two hours and thirty minutes.
David Leatherhoff's Axe : In the "Heaven" level, enter the code "26-16-4-27-49-2-32-45-12-23",
get the axe, then use it on a Twitcher.
Simon's Book : Successfully complete the game on the Nightmare difficulty with an "S" rank.
Use the following secret rooms to change costumes or equip items and weapons:
1.At the start of Chapter 1, enter the first door on the left after seeing the black figure walking away.
2.At the start of Chapter 6, search for a wrecked red car, and enter the trap door that is next to it.
Note: This room allows you to regain items and weapons that were lost after the train crash.