On June 1, 2009 it was announced according to the Valve channel and on June 18, 2009 on E3 giving us a video about what the game was about (in a beta version).

Then from June to August (more or less) the beta version was included in which it had different changes.
Such as:

• Weapons cut animations
  
• There was no L4D1 weapons
  
• The Scar was a fast automatic weapon instead of firing 3 bullets at a time
  
• You could not carry melee weapons in your secondary slot, but you can still take it
  
• Ammo upgrades was found around the map and could be used infinitely
  
• There is no death in animation, so there are no defibrillators, but there is ragdoll
  
• Survivors skins
  
• Infected skins
  
• Ceda Infected and fireaxe on The Parish
  
• No Jockey included
  
• Spitter spit was different and was actually goo that turned from green to yellow and red instead of being acid
  
• Charger had different ability, he still charged but he didn't grab the survivor and pummel them, since he just walked up to them and pummel them
  
• Spitter and Charger Bacteria sound was different
  
• Charger had different mortification music but the mortification hit sound still has the beta music
  
• Only campaing for Swamp Fever and The Parish

Then from November 3, 2009 they released the demo that includes almost the full game made with The Parish campaign with only two maps.

L4D2 was launched on November 17, 2009 with new weapons, new infected, new campaigns, new scavenge mode and more.


It was also released for the Mac version on March 8, 2010.

Valve announced the first free downloadable content that it includes only a 3-chapter campaign called "The Passing", with new infected such as "The Fallen Survivor", new models of common infected and a new Witch model (dressed in Bridal Veil). New weapons such as: The M60, the golf club and new resources such as the "Lockers". It also includes the "Mutations" game modes that is changing per week and other minor additions. Available from April 22, 2010.


Besides that the survivors l4d2 know the survivors of l4d1 and we know that one of them has died.

And here an order of each mutation that was published by Valve and some of the facts were made by the community that were officially approved and given.

1. Realism Versus 21/04/2010 (already included as a game mode)
   
2. Follow the Liter 07/05/2010
   
3. Last Man on Earth 28/05/2010
   
4. Chainsaw Massacre 04/06/2010
   
5. Headshot! 18/06/2010
   
6. Four Swordsmen 09/07/2010
   
7. Hard Eight 16/07/2010
   
8. Healthpackalypse! 23/07/2010
   
9. TAAANNNKK! 10/10/2010
   
10. Lone Gunman 22/10/2010
    
11. Bleed Out Versus 29/10/2010
    
12. Healing Gnome 05/11/2010
    
13. Gib Fest 19/11/2010
    
14. Riding My Survivor 14/01/2011
    
15. Nightmare 28/01/2011
    
16. Death’s Door 11/02/2011
    
17. Versus Survival 22/04/2011
    
18. Hunting Party 17/06/2011
    
19. Iron Man 21/10/2011
    
20. Confogl 04/11/2011
    
21. Flu Season 25/05/2012

On September 30, 2010 the new campaign The Sacrifice is announced


It includes 3 chapters a little longer than the previous DLC and with the "No Mercy" campaign from the previous game. It also includes weapons such as the M60 and in addition to playing again with the survivors of the previous game and a new model for the Tank that appears in the train of The Sacrifice. New mutations and a new explosive "The barrel", Available since October 10, 2010.

And also includes a comic about the previous stories of each survivors before they came together and part of the escape of the Blood Harvest campaign.
Left 4 Dead The Sacrifice Comic[www.l4d.com]

Also and more importantly, that seeing as a great character of the 4, is sacrificed to save his teammates / friends.

The next campaign they added from the creators of "Two Evil Eyes" came out Cold Stream which includes 4 campaigns, along with the 4 cover campaigns from l4d1 to l4d2: Crash Course, Death Toll, Dead Air and Blood Harvest. As of March 22, 2011, it was announced in beta.


Cold Stream has been in development since the beginning of 2011, however, being the largest content Valve has made for Left 4 Dead, it has been delayed for several months. It will be available for download from July 24, 2012 on Steam and was released on August 3, 2012 for Xbox 360. Unlike the first two DLCs, it does not have new weapons, but includes an option to choose any Mutations. Cold stream is not part of the main story of Left 4 dead and is therefore a campaign with the sole purpose of having fun.


They also announced for Linux.

On October 25, 2012 to celebrate the Halloween event and its great update, Valve has put a Free Weekend for new players to play and buy on offers. For recent players who already have the game purchased, the "Good Guy Nick" achievement is given to help free weekend players complete any campaign.

This achievement was the most difficult due to the lack of attention on the part of Valve in publishing free weekend followed by each month or depends on an event or offer. So far the most striking was May 25, 2018, then it was not well known if there was another one or when he will put it back on.

The Workshop was launched on January 17, 2013. Allowing the community to publish custom content be it campaigns, maps, mods, scripts, mutations, etc.

Here all the most popular mods that were given when the Workshop was launched: L4D2 Workshop

And here is a list of the most popular campaigns / maps:
https://steamproxy.net/sharedfiles/filedetails/?id=625654184
Note: This guide shows only on the gamemaps.com site. Search for campaigns by name in the workshop search engine.

On February 11, 2013, Valve announced a part of the installation of the Left 4 Dead 2 Beta, which includes part of the new advanced tool for moderators: EMS

What is EMS? It is vastly improved scripting system that allows script authors to go past modifying existing scripts and write custom script logic, spawn and control entities, and much much more.

Mod authors will now be able to create deep custom experiences that can be played on any map or tailor create something for new or existing maps.

We have included numerous examples including a new survival mode called Holdout, other all new game modes, and numerous other examples to help show mod authors how to use the new tools.

For example: the Admin System mod of "Rayman1103" contains scripts for EMS.

On July 2, 2013, the EMS tool is already released outside the beta. Where modders can now experience everything about scripts and their functions. Allowing them to create mutations or content vscripts.

For more information about EMS, here everything is summarized: L4D2 EMS

On December 25, 2013 to celebrate Christmas and with incredible updates they gave us, Valve gives as a gift the free game for a limited time and players can obtain it at no cost.

Players who already have the game purchased or are going to buy it, will get the achievement "Ghost of Christmas Present" (not including free players), which is based similar to Good Guy Nick, only you were to help players who They got the free l4d2 on Christmas of 2013 to complete any campaign.

This achievement is obtained forever, as long as you find those free Christmas players.

James R. French (September 28, 1928 - December 20, 2017) was an American radio personality and producer who has written and produced, as of 2011, over 803 radio shows, including The Adventures of Harry Nile and The Further Adventures of Sherlock Holmes series.

French became morning DJ on KIRO (AM) in Seattle in 1959. He later began production of Imagination Theatre, which in 2003 moved to KIXI-AM. His syndicated programs are now broadcast on over 120 stations in the U.S. and Canada, and are also heard on the XM Satellite Radio system all over North America.

He made an appearance on NBC's Pandora's Clock (1996) in the role of an Army non-com. He provided the voice for the Scientist in Gunman Chronicles, Father Grigori in Half-Life 2, the Fisherman in Half-Life 2: Lost Coast, Bill in the games Left 4 Dead and Payday: The Heist (as a cameo in the opening cutscene to one of the missions), and Elder Titan in Dota 2.

In late January 2017, it was formally announced via the Imagination Theater Facebook page that, due to age and health issues, Jim French and his family would be closing down their production company and discontinuing all broadcasts of Imagination Theater at the end of March 2017. French died on December 20, 2017 at age 89. He was predeceased by his wife Pat, who had died earlier the same year.

On November 1, 2018, Valve added fixed an "addonconfig.cfg" file that allows you to deactivate the addons in Versus, Scavenge mode and mutations related to those modes. This does not harm the campaign, realism and survival mode.

In this way the players who enter the official Valve servers cannot have the mods activated for those modes. Otherwise the host of the local server or its dedicated server may change the setting from 1 to 0.

The famous original and classic game, and for being named game of the year created by Turtle Rock Studios (bought by Valve) has reached its celebration of 10 years from November 17, 2008 to 2018.

A classic game with the survivors of l4d1, 5 special infected, common infected managers, 5 weapons, 6 campaigns, more atmosphere and so on.

With so many years and its expected moment has arrived. Left 4 Dead 2 has turned 10 from November 17, 2009 to 2019. A game developed by Valve and he has given us several updates with new content. And carrying the survivors of l4d1 for l4d2 and especially the workshop content.

Some of the games have been provided by Valve with some survivors of the L4D. In facts they are:

Resident Evil 6: From April 5, 2013, PC users can choose Coach, Nick, Ellis and Rochelle from L4D2 in The Mercenaries No Mercy (Resident Evil 6) mode, with weapons created for the occasion, in addition to the cameo of two of the most enemies iconic: the Witch and the Tank.

Zombie Army Trilogy: August 20, 2015, as part of a free update, the eight protagonists of the saga are available as playable characters (Bill, Coach, Ellis, Francis, Louis, Rochelle and Zoey).

Dead by Daylight: On March 8, 2017, as part of the "Left Behind" DLC, Bill's character as Survivor is available. But compared to other crossovers this seems to be the direct continuation of what happened to him after the "The Sacrifice" campaign, his full name is also revealed here: William "Bill" Overbeck.

Payday No Mercy: there is a mission entitled "No Mercy" in which the protagonists of it have to go to the Mercy hospital (which appears in Left 4 Dead) and have to steal the blood of an infected patient and escape, in the mission they can wear the masks of the infected of the game for the characters, you can meet Bill in an elevator, and there is an alternative ending in which it seems that the protagonists of Payday initiate the infection of Left 4 Dead.

In Payday The Heist was released on July 26, 2012 and in Payday 2 on October 30, 2018.

Warhammer: The End Times – Vermintide: is a first-person video game developed and published by Fatshark. The game is set in the Warhammer Fantasy universe. It was released for Microsoft Windows on October 23, 2015 and was released for PlayStation 4 and Xbox One on October 4, 2016. The game is multiplayer-only, and its structure is similar to Valve's Left 4 Dead series. Set in the End Times, players can team up with three other players to fight against the Skaven, a race of rodent-like monstrous creatures, in the city of Ubersreik. At the end of each match, the players are given the opportunity to roll dice, which determine the weapons they will receive as reward.

Earthfall: is a 4-player cooperative first-person shooter video game developed by American studio Holospark and published by Gearbox Publishing. It was released on July 13, 2018 for Microsoft Windows, PlayStation 4, Xbox One, and Nintendo Switch. In the game, players are part of a guerilla force fighting hordes of deadly alien invaders. The game has been called a clone of Left 4 Dead by critics. It received mixed to negative reviews, citing an overall lack of quality.

World War Z: On April 16, 2019, a new movie-based game was released and made a similar reference to the L4D2, especially with some types of zombies such as the Hunter, Chager, Ceda Infected, etc.

Dying Light: On October 24, 2019 the developers, with Valve's permission, launched a free DLC with the Left 4 Dead 2-style event, including 3 melee weapons: the electric guitar, the frying pan and the golf club.

Left 4 Dead survivors arcade: This afternoon Game Informer managed to get the first Gameplay trailer of the collaborative work between Taito and Valve of the Left 4 Dead Survivors arcade. The exclusive for Japan will be nothing more or nothing less than a direct port of Left 4 Dead 2 for publication in the eastern market.
Unlike the renowned characters of the game, Rochelle, Coach, Ellis and Nick, the Japanese version will feature new faces and voices, two men and two women so it can be appreciated, outside of it, there will be no change, they will remain for Now the same maps and gameplay. So far the details of how the arcade cabin will be unknown, but this doubt will soon dissipate when it is confirmed that the field tests of the machine are about to begin.
The controls for the arcade adaptation is a Wii Nunchuck-esque controller and a Razer Mouse in a Viewlix Cabinet.

Back 4 Blood: In 2019 Turtle Rock Studios together with Warner Bros announces a new game based on the zombie apocalypse "Back 4 Blood". By its name it indicates a successor of the Left 4 Dead, although they affirmed that it will not be a Left 4 Dead 3 and will not have anything to do part of its history. It is possible that by 2020, it is not yet well known.

I want to thank several people for sharing this great game and the best moments that have happened in recent years and what remains so far.

Valve & Turtle Rock Studios: Thank you very much for creating this beautiful game. This was undoubtedly for me one of the best I've played in my life.

The Community: Thank you very much for sharing some great things and watching some videos, photos, artwork, guides, mods, etc. No doubt you make the game more alive than ever.

Modders: Thank you very much for giving us personalized content, with the workshop, the gamemaps and the gamebanana make us believe things that are good for us to have more fun with this game and some bug fixes and glitches. And also some of the biggest campaigns and maps I've played.

Youtubers: Thank you very much for giving the game some humor and things we didn't know and could discover. You eventually make the game more fun with your ideas and creativity.

And as always, many, many, many and many thanks to all of you for sharing some fun moments with the game. May this be a memory we will never forget and follow what comes. Thank you :D