: Health kits, weapons, and ammunition are not fixed; the Director places them where they are most needed (or withholds them to increase tension) depending on the team's health and resources.
: In certain campaigns, the Director can alter the physical path of the level, such as changing the layout of a cemetery or shifting weather conditions like the torrential rain in the "Hard Rain" campaign, which directly impacts visibility and movement. left-4-dead-2-game
Beyond the AI Director, the game is renowned for its diverse cooperative and competitive modes , including , where players can control the zombies themselves, and Realism mode , which removes helpful UI elements like survivor outlines to create a more punishing experience. : Health kits, weapons, and ammunition are not