Valve has released a patch for Left 4 Dead that seems to be laying the ground work to make sure that things are in order before the release of the Crash Course campaign that is to be released shortly.

While it seems that most of what the patch does is actually behind the curtain, we know that several improvements to the game were included as part of this patch. The biggest enhancement might be the improvements to the HUD when players are on the side of the zombies in the versus mode. The zombie HUD now counts down the special attack recharge of the other infected teammates you happen to be playing with.

In addition to the zombie HUD enhancements, it would appear that additional achievements are to be added, as well, with the release of the Crash Course campaign. Previously, there were 50 achievements for Left 4 Dead, but after the patch the game is now showing a total of 60 achievements; the actual additional achievements are not showing up yet, but we suspect that they will once the Crash Course campaign is released.

The news that the Crash Course content will cost Xbox 360 owners, while PC players will get the content for free, seems to still be stinging in many of the Left 4 Dead discussions. Maybe the new patch will serve as distraction while users explore the new patch to find out what else Valve may have changed. Our sources tell us that in additional to the changes that are most visible, like the zombie HUD enhancement, a number of behind the scenes changes have been made to address some exploit issues, as well.