Left 4 Dead is a series of cooperative first-person shooter survival horror video games published by Valve. Set in the days after a pandemic outbreak of a viral strain transforming people into zombie-like feral creatures, the games follow the adventures of four survivors attempting to reach safe houses and military rescue while fending off the attacking hordes.
A sample series of encounters (with progress from left to right) during a level playthrough of Left 4 Dead. The top bar shows the original population of common (white icons), special (colored icons) and boss (large icons) procedurally generated by the AI Director prior to starting the level. The second bar is the monitored "Survivor Intensity", with the red "Relax" sections occurring immediately after the Intensity reaches a threshold limit. The third bar is the actual population generated while playing the level; certain common hordes have been removed due to the Intensity being high and in a "relaxed" state, while other hordes and uncommons have been added when the Intensity is very low near the end of the level.
Valve Corporation, also known as Valve Software, is an American video game developer, publisher, and digital distribution company headquartered in Bellevue, Washington. It is the developer of the software distribution platform Steam and the game franchises Half-Life, Counter-Strike, Portal, Day of Defeat, Team Fortress, Left 4 Dead, and Dota.
The lobby of Valve's former offices in Bellevue, Washington
Gabe Newell (foreground) and Doug Lombardi (background), 2007
Designer Robin Walker at Steam Dev Days 2014
