Forgotten Half-Life 2 zombie mod from 2007 suddenly explodes on Steam

If Half-Life is one of the most influential videogame series in history, it's not only because of Valve, Gordon Freeman, and the actual FPS games themselves. Half-Life and Half-Life 2 are nexus points for a whole generation of PC classics. Counter-Strike began as a Half-Life mod, as did Day of Defeat, and The Hidden. The first Team Fortress was bundled as a Half-Life spinoff. The same Source engine that brings to life City 17 and Ravenholm is also the backbone of Team Fortress 2 and Portal. Originally released in 2007, Zombie Panic Source is another of Half-Life's informal descendants. A spiritual precursor to today's asymmetrical, multiplayer horror games and a staple of mid to late '00s modding, alongside CSGO and Left 4 Dead, Zombie Panic Source is now somehow having a resurgence on Steam.

At the beginning of each match, you choose to play as either a zombie or a survivor. The humans have guns and melee weapons. The undead have can see in the dark and have deadly hand-to-hand attacks, and the more warmbloods they kill, the more abilities they unlock. Some variants can even turn human players into ghouls, thinning the ranks of the living while swelling the corpse army. Between State of Decay, Dying Light, Dead Island 2, and Project Zomboid (at least once build 42 wraps up), almost all of the best zombie games are multiplayer nowadays. But Zombie Panic Source was a forerunner. I expect everyone who played the Half-Life 2 mod can still hear the sound of 'Crackbone' in their heads: "I got them brain dawgs."

Based on data from SteamDB, nowadays, Zombie Panic Source still attracts an average concurrent playerbase of around 50. However, as of today, Monday July 14, the separate, dedicated servers for the multiplayer game have seemingly exploded in popularity, with more than 5,000 people seemingly playing Zombie Panic Source at the same time. So, what's going on?

On July 13, 2024, Half-Life and Source engine community site Lambda Generation promoted an event that encouraged Zombie Panic Source fans to log in and play the game together as a tribute to the mod and its legacy. It's now almost exactly 12 months later. While there doesn't seem to be any formal notice about a similar event for 2025, it's possible that fans have previously mutually agreed that July 13 is now International Zombie Panic Source Day, or something to that effect, which would explain why the player count has suddenly taken off.

However, the dedicated servers for a variety of other games have also suddenly been populated by large or unprecedented numbers of players. The amount of people using dedicated servers for CSGO, Left 4 Dead, Monday Night Combat, and Rebellion's Aliens Versus Predator has also skyrocketed during the past 24 hours.

In the case of Aliens Versus Predator, this is owing to a community initiative that was publicized on the game's Steam discussion page on Wednesday July 9. "Hey everyone," one AvP player writes. "This Saturday we're jumping back into Aliens Versus Predator for some classic chaos. Let's team up and make it happen." The player counts for some of the other games' dedicated servers seem to have spiked without attendant community events, however.

So, we need to dig a little deeper. If you're not yet aware of Stop Killing Games, it's an ongoing campaign to highlight potential consumer rights contraventions in the service agreements for online-only games. The initiative was created by Ross Scott, writer and director of the famous Half-Life machinima series Freeman's Mind, and it was initially a way to organize protests against Ubisoft for shutting down online services for The Crew, effectively making the game inaccessible.

Since 2024, Stop Killing Games has submitted petitions and letters to a number of governmental bodies around the world, catalyzing a groundswell of discussion regarding videogame ownership. Long story short, given the heightened awareness about the potential precariousness of online games and the possibility that multiplayer services can be suddenly shut down, it follows that players may increasingly turn to using private, dedicated servers, hence why we're seeing the current trend on Steam.

There is another possible explanation. If dedicated servers continue to attract large numbers of players, that could be a sign that Stop Killing Games and the discussions that it has provoked have motivated a change in how people play online games. If the numbers drop suddenly, that may signify some kind of coordinated bot attack - thousands of dummy accounts artificially boosting 'player' counts.

But remember Aliens Versus Predator. There, we have a community specifically organizing the play the game en masse simultaneously, followed by a big uptick in the amount of people using the dedicated server. In that case, at least, rather than a random bot swarm, it seems arguable that people are making a conscious decision to play, and play on the separate, dedicated server. Perhaps the same is true for the other currently trending games. We'll have to see.

If you're a Zombie Panic veteran, you might want to try some of the other best old games. Otherwise, if you want to totally overhaul your setup, check out our best gaming PC guide.

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