History ShoutOut / Left4Dead

* At one point in the Crash Course campaign, the survivors must pass through a small area with a broken steam pipe. Francis says "watch out for that steam pipe!", quickly followed by veiled references to a different kind of UsefulNotes/{{Steam}}.

* Something of an EasterEgg, there's a very small chance that, upon getting hit with friendly fire, Nick will say

** Fun Fact: Purple, gold and green are [[http://www.mardigrasneworleans.com/mgcolors.html the official colors of Mardi gras]] and LSU adopted the first two while rival Tulane took green.

-->"[[VideoGame/DeadRising Otis: Out of film. No helicopters. Zombies too fast. Not going to make it. --Frank West]]"
-->"[[Film/DawnOfTheDead1978 Roger, went to the mall --Francine]]"
-->"[[Film/DawnOfTheDead2004 Went to save my dog. If not back in 15 minutes, everyone drop everything and come save me. --Nicole]]"
-->"Looking for an M60? Come see me. --[[VideoGame/PlantsVsZombies Crazy Dave]]"
-->"[[Film/TwentyEightDaysLater REPENT. THE END IS EXTREMELY FUCKING NIGH.]]"
-->"[[Film/ShaunOfTheDead Ed is King of the Zombies]]"

-->"[[Film/{{Ghostbusters 1984}} He slimed me!]]"

--> '''Zoey:''' "Oh no, the Zombies killed God!"
--> '''Francis:''' "God's dead, huh? Well, join the damn club."

--> "Remember, Film/SoylentGreen is people!"

---> "Rule #32 – Enjoy the Little Things!"

--> '''Zoey:''' Man, I love steam.\\

* Upon picking up an SMG, Louis might say, "This is just like in ''VideoGame/CounterStrike''!". Which itself is a reference to how ''Left 4 Dead'' started when the dev team of ''VideoGame/CounterStrike: Source'' was messing around with playing as armed Counter-Terrorists against knife wielding Terrorist bots.
** Louis has an unused line in Left 4 Dead 2 for picking up a Crowbar. "Man, I feel like [[VideoGame/HalfLife Gordon Freeman!]]"

-->"Oh, nice, [[Franchise/EvilDead a cabin in the middle of nowhere]]. [[KillEmAll I know how this movie ends]]."

** And of course, her and Louis bond over it too, as Francis doesn't know he's referencing Evil Dead when he says it.
-->Francis, picking up a shotgun: "Groovy."
-->Zoey and Louis snickering
-->Francis: "What, it IS groovy!"
* There are countless shout outs to zombie movies ranging from things Zoey says to a room where you can see the remains of a zombie killed by a lawn mower.

* Sometimes when Zoey picks up a shotgun, she will say "[[Franchise/EvilDead Groovy.]]"
** Usually triggered right after Francis does; he has a similar line:
---> '''Francis:''' Groovy! ''(either Louis or Zoey snickers audibly)'' What? It ''is'' groovy!

--> "Rule #32 – Enjoy the Little Things!"

* One of the achievements added in The Last Stand update requires you to find and obtain 22 hidden golden crowbars in every ''Left 4 Dead 1'' survival map. The achievement's name? [[VideoGame/HalfLife "GOLDEN FREEMAN".]] The icon even shows Gordon's hand holding up a crowbar.