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The basic idea of Zombie Panic! Source is to create a solid gameplay that is based on a classic zombie outbreak scenario. The living dead are coming for the last remaining humans, and these survivors must fight them off and live through the day.

The game works like this:

At the start of each round, players can either choose to join the human team or volunteer to be the first zombie. If no one volunteers the game will pick one human randomly, and the game begins! The starter zombie's goal is to kill the humans while the human goal is to stay alive as long as possible, complete objectives, or even wipe out all the zombies. The catch is that when a human dies he will simply join the ranks of the undead, now ready to finish off his old living teammates. The humans can't tell by the player list who is alive and who is undead.

Eventually, there will only be one survivor still standing if everything goes wrong, his back against the wall while facing the animated corpses of his former allies. In a survival round, the zombies team only has a certain number of reinforcements (lives), and when a zombie is killed they lose a life from the counter. However, when a human is killed they gain 1 life. When the zombies run out of lives, the remaining survivors win the round by killing off the remaining undead left on the map. In objective rounds, zombies get an unlimited number of lives while the humans must complete a variety of map-based objectives to win.

Human abilities and advantages:

  • Speed - A zombie can only run at about 80% of the top speed of a human player. Though, the more weaponry and ammo a human picks up, the more it will slow him down, making him an easy target for the undead. If they are carrying nothing, a human can easily outrun a zombie. Watch out so you don't get cornered...
  • Weapons - The humans have a wide selection of weapons to use for defending themselves, like firearms, explosives and melee weapons. It is essential for humans to locate weapons and ammo around the map in order to survive, since they only spawn with a random melee weapon and handgun scavenging is a must. Remember that inventory space is limited and hogging weapons will merely slow a survivor down, so sharing with teammates is a must!
  • Numbers - At the beginning of the round, there are only from 1-3 zombies, depending on how populated the server is. Everyone else is a survivor. This means that they can easily watch each other's backs and provide cover fire. However, once their ammo starts to run dry and they begin to squabble amongst themselves for the few precious clips of ammo available.
  • Communication - Instead of typing messages to each other (occupying busy hands), which can be really dangerous when the zombies are lurking in the shadows, the humans have the ability to communicate by voice commands. There is a menu with several commonly-used commands that can help the survivors to organize a defense, trade ammunition and request help.
  • Panic! - Drop everything but what is in your hand and flee! This grants a temporary speed boost, allowing for a quick getaway, but use it wisely. More often than not, panicking just staves off a survivor's inevitable doom.

Zombie abilities and advantages:

  • Regeneration - Over time, zombies regenerate hit points, making it more difficult for survivors to make the undead dead.
  • Carrier - The first Zombie of the round differ a lot from the other undead - he looks different, sounds different, and has abilities that the average zombie can only dream of. He is the Carrier! With the power to infect people (10% infection chance per hit by default), he will cause panic and paranoia amongst the living. He also has the ability to roar, summoning other zombies to his aid.
  • Persistence - Zombies might seem to die often, but they won't give up. They just keep re-spawning over and over until your pistol runs out of bullets, your back is to the wall, and there is no escape.
  • Numbers - Later on in the game, as the undead ranks swell with a fresh dead, the last few humans will find their superior weaponry of small comfort for the hordes of zombies closing in.
  • Zombie Vision - Zombies can't use flashlights, so they have the ability to use Zombie Vision. Z-vision works in a way that it brightens up any possible light source in a room to make it more viewable. More importantly, when humans get tired, they start to glow blood red, making it easier for a zombie to track their prey. To prevent games of hiding and seek a survivor who just sits still will also start to glow red through sheer terror of the unknown.

We want the game to feel creepy and give you a sense of desperation, and yet not take itself so seriously that you can't laugh at the way you just died. Overall, fun and playability is the priority, and while realism and horror are important, those things are just a bonus when possible. We want a game that you can easily play with groups of any size, even with small or uneven numbers. Plus, there's a certain sense of satisfaction in tearing apart those heartless survivors who failed to protect you while you were alive, limb from limb.


See you there!

-Zombie Panic! Team

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RSS Articles

We're back with another developer update to reveal more upcoming content from the unstable build, including a special day celebrating 10 Years of Zombie Panic! Source on Steam!

Mod's Backstory

Zombie Panic! Source was initially released on Dec 28, 2007 via ModDB page as a Half-Life 2's modification beta. Back then, you were required to own any Source game to play the mod. Valve then opened a new door for mods to be delivered through the Steam platform on Oct 3, 2008. Five of these mods, including ZPS, were selected to be integrated using Steamworks Distribution, which helps streamline the delivery, installation, and update process.

It also consists of features like Steam Achievements, Steam Workshop, anti-cheat technology, management of user-generated content, etc. Getting Steam'd was a huge step to deliver faster updates and get connected with our community even more. We're very thankful for Valve developing such a great tool for the gaming platform.

To celebrate this memorable day, we've gathered exciting news regarding v3.1's development that is ready to be shown to the public!

How things are looking

We're very glad to retrieve two old melee concept weapons from the grave: the Tennis Racket and a Broom! These will be available in the unstable build for public playtesting before v3.1 public release. We'll need your help in providing feedback and ideas to adjust them for being viable in melee combat in the future. If you're thinking that we will only add melee weapons from now on, well, don't lose hope! While we're not yet ready to show them off to the public, take heart in that we have some ranged weapons that we're working on.

Melee Showcase

We're also pleased to announce the official unveiling of the Biotec facelift! Casei has given the facility a more high-tech, corporate look while retaining the essential classic gameplay which you've come to know and love. There are brand new 3D props by both Darb Dudeand Ratboy, new particle effects by Dr.Vodker, new areas with better textures and decals, lighting improvements, and general bug fixes!

With these upgrades being made, we're aiming to distribute the same devotion to our other stock maps imploring for improvements and fixes. Asylum redux and Biotec editions are just the beginning of a much longer evaluation and update process. This is a long-term goal for the mapping team, but it's also a delicate process that needs careful attention to balance and detail, and we hope the results are as pleasing as Biotec's, as seen below:

Biotec 1

Biotec 2

Feed-O-Meter Adjustments

We've decided to make a couple of improvements to the Feed-O-Meter's usage and Berserk mode. The Feed-O-Meter will now auto regenerate itself when not in use. The regeneration process is very slow and you still should use your feed bar wisely. The Berzerk, on the other hand, now has its own bar separated from the normal Feed-O-Meter bar. This will make the zombie's life easier while allowing them to manage which feature they would like to use without affecting or wasting a single berzerk bar while lunging. The Berzerk function remains untouched beyond that.

Feed o Meter

This is a heavily experimental change that will require a long period of testing to assure it's well balanced and fair for both teams.

Zombie Teammates Glow

An additional zombie feature has also been added to improve the team's communication and create better tactical ambushes against the survivors. Zombies will be able to see their teammates glowing through nearby walls, but with a minimal range that is more limited when compared to the Carrier's roar glow - without consuming one Feed-O-Meter bar.

Upgraded Voice Menu

We've improved our voice wheel menu system, based on Left 4 Dead's radial menu, adding one extra survivor line: "Keep Moving!". This was unused content for a long time. All current VO's survivors had this line recorded and ready to use, but the previous team never went further with it.

Voice Menu

Sadly, due to the changes in the voice system, we were forced to change our voice menu's default keys, replacing with new code commands, which is why you will have to reset your client configurations in Game Options > Keyboard.

Server Browser Info Box

Finally, we've recreated our entire server browser window from the ground up, designing two different server tabs when searching for a community server. We also implemented one server information box advising newcomers about their first connection to any ZPS server. Hopefully, with this new info box, new players will be aware which type of content they can expect out of that server.

Server Info Box

Vanilla servers running pure ZPS gameplay will be displayed in the "Internet" tab, while custom servers running any modified plugins will be relocated to the "Custom Server" tab.

We've exhibited a lot more upcoming content (Linux client support, hitboxes fixed, weapon barricade adjustments, ammo hud changes) created to improve your ZPS experience in our previous article.

Build Status

We're very excited to get the core functionality of the build into the hands of the community as soon as possible to begin our first public beta playtesting with you all. While not everything will be properly balanced and working at first launch, the unstable build is well-considered "playable" at this moment. Hooray!

Meanwhile, we'll keep scheduling our internal playtesting and start organizing the preparations of our public playtesting. Feel free to join our official Discord server to not miss anything from us and lose the opportunity to opt-in the beta right away!

See you during Halloween!

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- Zombie Panic! Source Development Team

v3.1 Development Update - First Look

v3.1 Development Update - First Look

News 8 comments

We'd like to finally announce and talk about some new features, improvements and other major changes in our next biggest upcoming ZPS update v3.1! Including...

June Development Status

June Development Status


We've created our own Steam Developer Homepage and Official Zombie Panic! Steam Group! You can follow us for latest updates, dev blogs, general updates...

v3.0.8 Update - Madhouse Mayhem

v3.0.8 Update - Madhouse Mayhem

News 4 comments

We're pleased to finally announce an incredible visual and gameplay overhaul to Asylum and some information regarding our next update!

v3.0.7 Hotfix-2 Changelog & SourceMod Support

v3.0.7 Hotfix-2 Changelog & SourceMod Support


While we focus our work on the v3.0.8 code rewriting, we're re-releasing v3.0.7 as a hotfix today. This update contains many bug fixes which were supposed...

RSS Files
WorkHazard OST

WorkHazard OST


Pithole (WorkHazard) OST made by our sound designer KaempeLaeske

Zomboeing OST

Zomboeing OST


Zomboeing OST made by our sound designer KaempeLaeske.

FrozenHeart OST

FrozenHeart OST


FrozenHeart OST made by our sound designer KaempeLaeske.

ZPS - Horde

ZPS - Horde

Music 2 comments

New Zombie Panic: Source ambient track "Horde" - By KillahMo

ZPS - Barricade System

ZPS - Barricade System


Zombie Panic: Source v1.5 will introduce the ZPS Barricade System. Here is a short preview of it in action. (Note: The HUD display is not visible in the...

ZPS - Descent

ZPS - Descent

Music 1 comment

New Zombie Panic: Source ambient track "Descent" - By KillahMo

Comments  (0 - 10 of 2,917)

Nice to see updates here!

Reply Good karma Bad karma+2 votes


a coop mode vs bots/npcs have been added?

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Tabajara77 Creator

It will always be PvP (Human players vs Zombie players). However, there are servers who host against BOTs with modified plugins. Plus, you can solo test mode by adding BOTs (but they don't have actual AI).

Reply Good karma+1 vote

Holy crap! You guys are still alive!? I'm astounded that you've been able to pull through since 2009!

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Tabajara77 Creator

Still alive and kickin'!

Reply Good karma+6 votes

Wow, you guys left out Win XP, that's sad...

Reply Good karma Bad karma+1 vote

Will you add any Weapons that were in Contagion into ZP:S?

Like the Bows and Rifles?

Or are you gonna stick with what you already have?

Reply Good karma Bad karma0 votes

Holy crap, I had no idea this was still being updated. I used to be super involved with the forums way back in like 2009, making maps and stuff. Maybe I'll download ZPS again and see if people are still playing on Cabin. The worst map.

Reply Good karma Bad karma+1 vote

do you accept donations ?

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Tabajara77 Creator

We're not accepting donations. It's a free mod. Only way to support us is sharing this mod with your friends!

Reply Good karma+3 votes
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1247 votes submitted.

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Highest Rated (13 agree) 10/10

Well...this is the greatest HL2 mod I've ever play! and i hope you guys can keep your hard works on the new mod! it looks awesome!

Dec 15 2010 by oceaneyes


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