Developed by the community, Left 4 Dead 2's recent The Last Stand update added a ton of massive new additions to the iconic PC staple, including fresh animations, melee weapons, and lines of dialogue. For a game that originally released all the way back in 2009, it's surprising to see such a major influx of new content, with the pack only reigniting the large fandom that surrounds the zombie-massacring classic.

Perhaps the biggest feature added in the update was a campaign also called The Last Stand, which evolved a former modded survival map by the same name into a fully-fledged Left 4 Dead experience. It takes players through a fun "what if?" scenario, where they eventually wind up in a derelict lighthouse and must survive against seemingly endless swarms of zombie foes.

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Thanks to Valve News Network, fans now know a lot more about this ambitious new slice of Left 4 Dead action, with several members of the community-led team behind the update holding a developer's commentary playthrough with the YouTube channel. Spanning just over 18 minutes, the video features developers Xanaguy, NF, and Roko, with the trio being very open about their time working on the official new Left 4 Dead 2 expansion. Through their playthrough of the campaign, they bring to light some hugely fun background secrets about the update as well as easter eggs they sneakily slotted into corners of the map.

A good example of the latter occurs towards the beginning of the video, with the team highlighting a tribute room dedicated to the extensive number of developers who worked on the game. The room features the names of every contributor etched into the wall alongside a golden crowbar players can fight with. According to The Last Stand devs, every contributor who worked on the game has an easter egg in the campaign, with NF revealing his as a reference to his former competitive team, ZSN, which can be found on the wall of the contributor room. Other things discussed in the playthrough are the team's insistence on making infected in versus able to spawn in trees, the meaning behind the graffiti on the walls, and how the game's junkyard area was originally envisioned as a landfill.

All in all, the team offers some incredible insights into how the update was made and the stages the campaign went through on its path to release. At the end of the playthrough, the host of the video, Tyler McVicker, asks the three developers if they have any ideas for more content if Valve gave them the go-ahead to release another update. Interestingly, they all seem pretty invigorated by the idea, with NB telling McVicker that "ideas are like a dime a dozen, but yeah, I have millions of ideas."

Left 4 Dead 2 is out now on PC and Xbox 360.

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