Left 4 Dead 2 is celebrating its 15-year anniversary today, November 17, 2024. Below, we look at how its cast and their interactions set it apart from its contemporaries and modern imitators alike.

Left 4 Dead 2 has been rightfully receiving its flowers for the past 15 years. The modding community has come up with everything from visual enhancements like improved blood textures to completely user-made campaigns. The last two DLCs for the game, Cold Stream and The Last Stand, were made by community members and officially endorsed by Valve. At the time of writing, there are over 45,000 players in-game on PC, and (if you somehow still don't own it) you can play it for free during this anniversary weekend. As such, the Steam discussions are filled with dozens of threads about the Good Guy Nick Achievement, which can only be obtained when the game is on a free weekend, something that occurs every couple of years.

But there's a special legacy Left 4 Dead has left behind: Valve's shooter has been a catalyst for a new subgenre altogether. Games like Back 4 Blood and The Anacrusis follow the formula closely, which isn't surprising considering the development teams include people who worked on Left 4 Dead. Others, such as Warhammer: Vermintide, Deep Rock Galactic, and Aliens: Fireteam Elite iterate on the concept of a co-op shooter by leaning closer to its own worlds, taking inspiration from existing franchises or coming up with brand-new mechanics to stand out from the rest. Yet, as more developers are taking the genre in interesting new directions, there's one crucial element that is often overlooked in these iterations.