Pace Yourself to the Tempo of the Game

This is the one rule that almost nobody follows, and it's a shame. Left 4 Dead has a very distinctive tempo associated with it. Those teams that move too fast end up drawing groups of zombies with them, endanger each other with multiple attacking special zombies, or trigger witches without realizing it. Conversely, if a team sits around in an area too long, the AI director will spawn increasingly harder waves to get them to move forward. It'll even spawn Tanks! The base tempo of the game is that you have time to do a quick sweep of each room along the main path and kill the zombies inside. If you use this tempo to pace yourself, you'll find that Left 4 Dead is challenging without being impossible!