Valve has revealed some details about the upcoming demo for Left 4 Dead 2, and that pre-order customers can get it a week before the great unwashed masses via Steam.

The demo resides in 'The Parish' campaign, where 1-4 players can get a taste on Xbox 360 and PC. It includes the new boss infected and melee weaponry. It's public on November 3rd.

"The Left 4 Dead 2 demo will feature gameplay taken from "The Parish" campaign, set in the New Orleans French Quarter," announced developer Valve.

"Adding new Survivors, boss zombies, weapons, and items, Left 4 Dead 2 offers a much larger game than the original, featuring more co-operative campaigns, more Versus campaigns, new Survival maps, and the new competitive game mode, Scavenge, all available at launch."

The demo is live on October 27th for pre-order customers from participating retailers, and will be publically made live November 3rd for PC gamers and Xbox Live Gold subscribers. Those without Gold Live membership will have to wait until November 10th on Xbox 360.

All the new infected zombie boss types and swinging melee weapons from the full game are included in the demo of Left 4 Dead 2. It releases on Xbox 360 and PC this November 17th.