Template:Didyouknow


 * ...the tattoo on Francis' shoulder can also be seen on the ring Nick wears on his right hand possibly hinting a connection with the two.
 * ...the Hunter doesn't have eyes. Despite this, he can still somehow see.
 * ...the coffee mugs found in various levels that state "Layoffs anyone?" and "What's Sleep?" are imported directly from Valve's Counter-Strike?
 * ...in the second level of Dead Center, Large Decontamination Trailers can be seen with text on the side humorously reading "Disease Emergency Assessment Dispatch", or D.E.A.D.
 * ...Bill is the only one in the introduction video to wield a tier 2 weapon.
 * ...the Charger hanging in Swamp Fever is done so in the shape of a Lambda, which serves as the logo for Half-Life?
 * ...there was originally an Infected in Left 4 Dead called the Screamer. It would wander around until spotting the Survivors and would then run away and utter an ear-piercing scream that summoned a horde. He was later cut and his ability was passed on to the Boomer.
 * ...the pills used in-game were based directly off of the Target brand of Ibuprofen?
 * ...in the original development, there was no linear path in Left 4 Dead campaign chapters and Survivors were free to roam the city before finding the safe room? This however proved to be too confusing as play-testers found themselves lost amongst the levels.
 * ...an X-ray found in Mercy Hospital bares a striking resemblance to that of a Spitter?
 * ...Francis has a Lambda shaved into the right side of his hair?
 * ...In the very first trailer of Left 4 Dead, Bill was killed by a Smoker, something that would be quite a difficult task considering the Smoker has a weak claw attack.
 * ...Bill's trademark cigarette never goes out unless he's either dead, or at the beginning of the introduction video?