These games use special joystick interface configurations that may interfere with the usability of the keyboard and mouse - if you wish to undo these configuration changes, there is a second configuration file you may run by opening the console and typing exec undo360controller then pressing enter.
For more information on enabling and using the console, please see the Console article.
To use this configuration, simply open the console and type exec 360controller then press enter. Half-Life 2: Episode 2, Portal, Team Fortress 2, and Left 4 Dead have their own built-in configuration for the XBOX 360 controller.
