Valve released an update through Steam recently that aimed at speeding up the load times and level-transitions in Half-Life 2 along with some updates for Steam and the Source SDK:Steam
* Source MODs will now automatically appear in the games list
* Improved startup process for Steam
* Fixed crash when creating a backup that would span multiple DVDs
* Fixed a bug that would unnecessarily validate Steam caches after a cache corruption
* Fixed Condition Zero: Deleted Scenes and Codename Gordon failing to backup correctly
* Fixed a bug where the message "the game files will be deleted and re-acquired" would repeat
* Fixed offline mode failing after not connecting to Steam for more than a month
Half-Life 2
* Optimization to the Steam filesystem to reduce game launch and level transition time
Source SDK
* Simplified debug-launch process for MOD developers. MOD developers no longer need to place a config file in their directory
* Added a registry key for MOD developers to use to locate a user's Steam installation located at HKEY_CURRENT_USER\Software\Valve\Steam\SourceModInstallPath
