Left 4 Dead (Game of the Year Edition) Cheats (PC)

In Part 1 (The Rooftops), as soo as you start, look over the edge of the building,
down to the street.  There's a box partway down, possibly an air conditioner.  Hop down to
that and it should reduce you to 41% life.  Drop to ground from there to skip the interior
of the apartments entirely.

To insert the cheats below, call-up the in-game cheats console by pressing the tilde (~)
key. Then, insert the cheats on the left for the corresponding result on the right.

Buddha - Receive damage, but will not die

give X - Give any item (where X = item name)

god - God Mode

impulse 10 - All weapons and ammunition

nb_blind 1 - Infected cannot see you

noclip - Walk through walls

sv_infinite_ammo 1 - Infinite ammunition (no reloads)

warp_all_survivors_here - Teleports all survivors to your position

warp_all_survivors_to_checkpoint - Teleports all survivors to the nearest
checkpoint

warp_all_survivors_to_finale - Teleports all survivors to the finale

warp_to_start_area - Teleport yourself to the next chapter

The infected cannot extinguish fires once they are ignited (all modes - but especially in
versus mode). Use that to your advantage in the campaign by using the molotov (or igniting
gas cans) on tough targets like Tanks and Witches.

If you need to 'reset' your primary weapon to its original (cherry) state, pick up a
weapon different from yours, then re-select the weapon you want. This is faster than
reloading (plus the time used from replenishing from the ammunition pile), and can help in
close-call rescue finales.

When reloading any weapon, your survivor can keep attacking with the melee button. The
reloading sequence will continue unabated.

If you'd like to "refill" your health as a zombie, run away from the survivors until you
see a message claiming you are too far away.  Now you'll be allowed end your current life
and then respawn back in the fray.  Hopefully they won't make it to the safe room before
you're back!

As the director's commentary points out, the Tank can be outrun by any survivor with green
(51% or more) health, but the Tank can overtake any survivor with 50% of less life,
because the more injured a survivor is, the slower s/he moves.

Pain pills will boost the speed of an injured survivor, although the color of the life bar
will reflect his/her original health status.

Alternate tapping the melee button and the weapon switch button rapidly to double your
melee speed.  This can be useful for beating off zombies on Expert difficulty.  Note: This
may be banned in Versus mode.

In Part 2 (The Crane), jump on the fence by climbing onto the vent cover. Head
across the fence and jump to the other side of the horizontal fence. Turn left, and head
to the end, jumping up and to the right to the AC unit / box on the corner of the next
building, allowing you to bypass the crescendo event. On the next building, go to the left
corner and jump into the highest branch of the tree below. You may lose up to 80% of your
health, so heal up before you leap. This leaves you right at the next safe room.

In Part 3 (The Construction Site), by the barricade that you burn is a metal door
and a raised fence. Jump on the railing / fence and follow it until it begins to start
downward. Here, hop onto the metal siding / door (a difficult maneuver).