"So how does it work? Essentially, the game is broken down into a series of units, with each unit representing a room, hallway or path to other rooms. Once the game is running, Soul Reaver stores three of these units in memory at any point - the room the player is standing in and the two adjacent units. As the main character moves into a new unit, the furthest one from the player that resides in memory is cleared and the next one loaded. Maps are designed so that loading a new unit into memory requires less time than it takes the player to cross the current unit. Clever, right?"