No Mercy



No Mercy is the first campaign in Left 4 Dead, spanning five chapters. Picking up right where the game's intro cinematic ends off, the Survivors are told by a passing helicopter to get to Mercy Hospital to be evacuated. On their trek to the hospital they must endure Infected-filled apartment buildings, city streets, subway tunnels, and sewers, until they finally reach the roof of the hospital itself to be rescued by helicopter.

Official description
The No Mercy campaign finds you on the rooftop of an obliterated apartment complex, deep in the heart of the once-thriving metropolis of Fairfield—now completely overrun with hordes of Infected. A voice from a bullhorn calls out from a rescue helicopter: Get to the roof of nearby Mercy Hospital and be airlifted to safety. Even if it means shooting your way through narrow alleys, open sewers and seething waves of zombies to get there.

It should also be noted that at the end of the intro video the survivors rest ontop of the apartment complex. There is incredible detail, even the dead body propped against the wall looks exactly the same in game as in the video.

Writings on the wall
The Apartments level contains graffiti throughout the map. Much of it is located in the safe room across the street, but some is found on the level start area. "Hope" is spray painted in large letters to the left of the doorway, with NO written above it to change it to say "No Hope", and "Morbid" can be seen on the right wall, also in graffiti style lettering.

In the safe room, "None of you will survive" and "Entire city is infected, if you can read this, get out", among other things written by other survivors.In the finale on the wall is a written conversation talking about the duration of the change to infected after being bit from 5 days, 3 days, 1 day, 2 1/2 hours, to final, 5 minutes.

Demo
The Left 4 Dead demo consisted of The Apartments in its entirety, as well as most of The Subway. The rest of the campaign could be seen in the demo if players went into NOCLIP mode.