Cooldown

Cooldown is the minimum length of time in Left 4 Dead that a Survivor or an Infected needs to wait after using an ability before they can use it again.

The Survivors
''Main article: Melee

The Survivors have no special abilities and therefore does not need to wait to use their abilities other than healing, shooting and reloading, but there is an exception in Versus Mode called Melee Fatigue. After couple of Melee uses, the Survivors will need to wait 2 seconds until they can use it again, and if they will keep using it, they will have to keep waiting 2 seconds each melee attack until fully rested for couple of seconds.

Originally this was not in the game until Valve received complaints of people not actually "Firing their gun" in Versus and Campaign matches. When the Left 4 Dead DLC known as the Survival pack came out, the developer added in this new system but left it out from the Campaign mode for unknown reasons.

The Infected
The Infected have different abilities, and therefore different cooldown times.


 * The Boomer has to wait one minute before able to vomit on the Survivors once again.
 * The Hunter does not have a cooldown on Pouncing, but it must wait 2 seconds before able to start leaping around if stood up.
 * The Smoker will have to wait 5 seconds if it missed it's prey, but if caught his prey with it's tongue and then failed/successfully killed, it will have to wait 15 seconds.
 * The Tank's only ability is to throw rocks, and requires 3 seconds to do so.

Other than the Infected's abilities, their "claw" attacks has a cooldown of 1 second.