This walkthrough was written by Georgi Samaras, also known as "sophialeigh" on GameFAQS.
This walkthrough was written while playing on Hard mode. The only notable difference between Hard and Normal is that enemies are tougher, deal more damage, and firearms carry less ammo. Puzzle solutions and strategy remain unchanged. All directions given (north, south, etc.) are given in relation to the map, but left and right are used in relation to Alex's position.