Demo

The Left 4 Dead demo was initially released on 6 November, 2008. It contains the first two chapters of the No Mercy campaign, playable in the Survivors' co-op mode, both locally and online. Initially, through a series of console commands, players could play as the Infected. This ability was removed in a 10 November, 2008 update.

The demo was released to the public for Xbox and PC on 11 November, 2008.

Preorders
The demo for Left 4 Dead was originally intended for those who pre-ordered the game through the Steam network or through Gamestop or EB Games. Those who ordered through Steam received the demo automatically and instantly, however, people who used Gamestop needed a demo code e-mailed to them. Many did not get theirs on time, adding to the already negative outlook on Gamestop. Additionally, Gamestop.com's system of distributing codes contained a glitch that allowed you to enter a random set of numbers or even leave the transaction code blank and still receive a code. Glitchers swarmed the site and received many codes without pre-ordering.