Ballistics Report

Pros

Co-op Game play
Too many games lack any support for co-op, instead opting for traditional deathmatch, so it is fantastic to see a major release being built from the ground up on the premise of teamwork. Valve set the standard with Team Fortress 2 and has only refined it with Left 4 Dead.

Play as a Zombie
The Zombie Bosses are truly unique in their abilities and function, and the result is a type of game play that is truly innovative and never before seen.

Audio
I dare anyone to approach the Witch with a positional surround system, in the dark, in the middle of the night, during a lightning storm, in the middle of the Winter Solstice. You may not jump, but I bet you will have trouble sleeping for a few hours.

Performance
Since it is built on the Source engine, L4D can run on pretty much any modern hardware configuration you can find today, making it easily one of the most scalable games released this year.

Cons

Connection Issues
Valve is using a unique matchmaking system with L4D that automatically drops you into a server with other players, but we have experienced some connection issues when loading levels or in the middle of games.

Mouse Bindings
Left 4 Dead seems to have issues with mouse buttons, preventing them from being detected if they are held down.