Featured in the demo are the first two parts to the No Mercy scenario. Those over at Left 4 Dead 411 have found some interesting goodies in the pre-load files. There are overhead maps of the areas, and two videos. One is the background that plays at the main screen while the other is the video that plays at the end asking that you purchase the full game!

The demo does introduce the new Matchmaking system for Valve's online games. Left 4 Dead is the only title that features the system, and there is a lot of idle speculation going on from the community about its use. "Will we have access to the server we rent for the game" is the biggest concern right now. A wait and see strategy is the best bet right now.

Let's not forget that Steam Cloud is also being rolled out with this release. The first version of the system will save your game configurations. Enjoy the early access demo!