Valve updated Left 4 Dead today with some great gameplay changes. One of which corrects my personal pet-peeve with the Boomer; his vomit will sometimes be deflected by normal infected who get in the way. Full list of changes:

Game and client changes

• Introduced fatigue to the melee attack in versus mode. You will see a HUD display when your melee swing is cooling down
• Boomer vomit will now pass through common infected
• Addressed some surround sound detection issues
• Fixed a rare crash when exiting Left4Dead on Windows Vista
• Fixed a case where the complete all expert campaigns achievement was not being rewarded

Dedicated server changes

• Corrected an issue where Windows based dedicated were sending spurious shutdown notifications to the master causing them to delist temporarily
• Fixed dedicated servers not resetting the versus team swap correctly–you could join a dedicated server that had a previous game that was swapped and arrive on the other team than what was selected in the lobby
• Renamed the tags for sv_search_key to use “key:” in the server tags instead of “sv_search_key.” This should help with issues of the 63 character limit of server tags
• Fixed an occasional server crash related to voting