Finish Chapter 1 - The Admittance.

Finish Chapter 2 - The Rooftop.

Finish Chapter 3 - The Infant Ward.

Watch a Man die and obtain his Handgun.

Solve the Puzzle and obtain the Shotgun.

Finish Chapter 4 - The Cleaver.

Finish Chapter 5 - The Courtyard.

Finish Chapter 6 - The Electric Buzz-Saw.

Find all three Keys and obtain the Electric Buzz-Saw.

Grab the Machine Gun in the Security Room.

Finish Chapter 7 - The Main Security Room.

Finish Chapter 8 - The Flashback.

Grab the Revolver from the Corpse.

Finish Chapter 9 - The Hole in the Wall.

Finish Chapter 10 - The Torn Photograph.

Remember a special Date and obtain the Sniper Rifle.

Finish Chapter 11 - The Guard Tower.

Finish Chapter 1 - The Admittance without picking up the Flashlight.

Obtain the Sniper Rifle in Chapter 5 - The Courtyard and before picking up any Photograph Fragment.

Finish Chapter 12 - The Cleaver's Return.

Finish Chapter 13 - The Door with no Handle.

Finish Chapter 14 - The Wheelchair's Return.

Finish Chapter 15 - The First Encounter.

Finish Chapter 16 - The Final Encounter.