The latest update introduces the ability to spawn more complex entities such as miniguns, ammo and doors. GET UPDATING :D

Well for some advanced features you are going to new SourceMod.

Here is a tutorial on how to install SourceMod.
http://blog.theevilpc.com/2009/03/how-to-install-metamod-sourcemod-on.html

Well basically the SVN shot itself in the head and it took me about an hour to recover it. There is a small chance of problems in the files..

It may make you redownload the CFG folder again which isn't very big.

I added a batch file called Install CFG which should overcome the problem with the latest update. I copies the system files into the L4D cfg folder so the game can use them.

Well thanks to Valve, addons no longer allow files other then materials, sounds and models. So I am working on a fix to correct all these problems!