SAS: Zombie Assault 4

Ninja Kiwi

Released: Oct 16, 2017
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Last updated: 15 Sep 2026, 19:44 GMT

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15 posts

24 Feb 2026Developer post
Zombie Assault: Resurgence - Demo Live Now!
The Zombie Assault: Resurgence demo is live now as part of Steam Next Fest! This demo is designed to showcase the core gameplay loop, progression systems, and co-op experience at the heart of Zombie Assault: Resurgence, so let’s break down what’s included… What’s in the Next Fest
The Zombie Assault: Resurgence demo is live now as part of Steam Next Fest! This demo is designed to showcase the core gameplay loop, progression systems, and co-op experience at the heart of Zombie Assault: Resurgence, so let’s break down what’s included…
What’s in the Next Fest demo?
Weapons, Gear, & Support
Common and Uncommon guns, giving you access to a solid range of weapons from the likes of HVM, Critical Mass, Ronson, and more!
Weapon upgrading - allowing you to push your favorite guns further.
Common and Uncommon Mods to start customising your weapon builds.
Common and Uncommon Armour to round out your loadout.
An HVM Grenade and Turret, letting you experiment with crowd control, area denial, and defensive playstyles.
The idea is for this setup to let you explore build variety, and set the stage for rarer gear later on.
Mercenaries & Progression
Three playable Merc classes:
Assault
Heavy
Medic
Access to Base Skills and Class Skills, allowing early customisation
Player level cap of 12 for the demo, ensuring steady progression without spoiling late-game systems.
Maps & Missions
Jump into three distinct environments:
Mining Facility
Abandoned Colony
Icefield
Across these locations, you’ll be able to play a range of mission types:
Eradication
Eradication Surge
Cache Recovery
Uplink
Close the Breach
Each mode highlights different pacing and teamwork dynamics, from pure combat to objective-driven survival!
Enemies & Encounters
Two terrifying boss encounters:
Regurgitator
Shredder
A selection of Zombie vs Player elemental effects, showcasing how damage types matter.
Zombie Mods and Buffs, adding unpredictability and forcing on-the-fly adaptation.
Systems & Social Features
USI Bounties, giving you passive goals and extra rewards as you play.
Access to Merc HQ - your hub for matchmaking, loadouts, upgrades, and prep between missions.
Various social features
Rich presence support for Discord and Steam
View Discord and Steam friends lists in-game
Invite Discord and Steam friends to your party (Both from within the game UI, and from the Discord/Steam UI)
In-game UI for pending party invites from Discord friends
Full text chat powered by Discord - available in Merc HQ, pre & post-game lobbies, as well as during a mission!
A Snapshot of Zombie Assault: Resurgence
This demo represents a vertical slice of ZA:R, providing enough content to let you test builds, experiment with classes, and fight some truly nasty hordes, while still leaving plenty of systems, weapons, and challenges for the full release. We’ll be watching feedback closely throughout Next Fest. What feels great, what needs tuning, and what you want more of will directly help shape the road ahead, so please don’t be shy in sharing your feedback with us!
Community Kill Count Challenge: Earn an Exclusive Weapon at Launch!
To say thank you to everyone jumping into the Steam Next Fest demo, we’re running a global community challenge for the entire duration of the event!
During the demo, every zombie kill counts toward a shared global total. If the community hits the target by the end of Next Fest, everyone who participated in the demo will unlock an exclusive weapon at full launch - the Morlok Frostbite Pistol!
The Morlok Frostbite is a unique, cryo-based pistol that won’t be obtainable anywhere else at launch. Forged by Morlok engineers, this Pistol packs enough force to take a target off their feet, and combined with Morlok's LN2 rounds, you have plenty of time to pick your shots!
Deliver cryo damage, slowing and controlling enemies
Reward precision and crowd management
Stand as a permanent badge of participation for those who helped push the community over the line!
We’ll be tracking progress throughout Next Fest via zombieassault.com, so whether you’re playing solo or in a full squad, every undead you drop helps the entire community!
Key Information
Steam Next Fest: February 23rd - March 2nd (Steam Store Page here!)
Earn an exclusive Pistol at launch by helping complete the Global Kill Count Challenge running throughout! (Track progress via zombieassault.com)
Play with the devs! We will also have some of the ZA:R devs looking to squad-up throughout Next Fest, so be sure to join our Discord (discord.gg/ninjakiwi) for further details on that when the time comes.
Ten-Hut, Mercs! Jump into the action now and don't forget to wishlist the game :D
Original post
30 Jan 2026Developer post
Zombie Assault: Resurgence - Dev Diary #13 - Steam Next Fest!
Ten-Hut, Mercs! It’s the first dev diary of the year, and it’s a good one! We’re incredibly excited to share that a demo version of Zombie Assault: Resurgence will be participating in Steam’s Next Fest, running from February 23rd to March 2nd ! For many of you, this will be the f
Ten-Hut, Mercs!
It’s the first dev diary of the year, and it’s a good one! We’re incredibly excited to share that a demo version of Zombie Assault: Resurgence will be participating in Steam’s Next Fest, running from February 23rd to March 2nd!
For many of you, this will be the first time you’ve been able to get hands-on with the game. For others, it’ll be a good opportunity to see what has changed since our last public playtest! We’ve been very intentional with what we’ve packed into this demo, with enough content to get a feel for the systems, classes, and chaos, while still leaving plenty of surprises for full launch.
This demo is designed to showcase the core gameplay loop, progression systems, and co-op experience at the heart of Zombie Assault: Resurgence, so let’s break down what’s included…
What’s in the Next Fest demo?
Weapons, Gear, & Support
Common and Uncommon guns, giving you access to a solid range of weapons from the likes of HVM, Critical Mass, Ronson, and more!
Weapon upgrading - allowing you to push your favorite guns further.
Common and Uncommon Mods to start customising your weapon builds.
Common and Uncommon Armour to round out your loadout.
An HVM Grenade and Turret, letting you experiment with crowd control, area denial, and defensive playstyles.
The idea is for this setup to let you explore build variety, and set the stage for rarer gear later on.
Mercenaries & Progression
Three playable Merc classes:
Assault
Heavy
Medic
Access to Base Skills and Class Skills, allowing early customisation
Player level cap of 12 for the demo, ensuring steady progression without spoiling late-game systems.
Maps & Missions
Jump into three distinct environments:
Mining Facility
Abandoned Colony
Icefield
Across these locations, you’ll be able to play a range of mission types:
Eradication
Eradication Surge
Cache Recovery
Uplink
Close the Breach
Each mode highlights different pacing and teamwork dynamics, from pure combat to objective-driven survival!
Enemies & Encounters
Two terrifying boss encounters:
Regurgitator
Shredder
A selection of Zombie vs Player elemental effects, showcasing how damage types matter.
Zombie Mods and Buffs, adding unpredictability and forcing on-the-fly adaptation.
Systems & Social Features
USI Bounties, giving you passive goals and extra rewards as you play.
Access to Merc HQ - your hub for matchmaking, loadouts, upgrades, and prep between missions.
Various social features
Rich presence support for Discord and Steam
View Discord and Steam friends lists in-game
Invite Discord and Steam friends to your party (Both from within the game UI, and from the Discord/Steam UI)
In-game UI for pending party invites from Discord friends
Full text chat powered by Discord - available in Merc HQ, pre & post-game lobbies, as well as during a mission!
A Snapshot of Zombie Assault: Resurgence
This demo represents a vertical slice of ZA:R, providing enough content to let you test builds, experiment with classes, and fight some truly nasty hordes, while still leaving plenty of systems, weapons, and challenges for the full release. We’ll be watching feedback closely throughout Next Fest. What feels great, what needs tuning, and what you want more of will directly help shape the road ahead, so please don’t be shy in sharing your feedback with us!
Community Kill Count Challenge: Earn an Exclusive Weapon at Launch!
To say thank you to everyone jumping into the Steam Next Fest demo, we’re running a global community challenge for the entire duration of the event!
During the demo, every zombie kill counts toward a shared global total. If the community hits the target by the end of Next Fest, everyone who participated in the demo will unlock an exclusive weapon at full launch - the Morlok Frostbite Pistol! Concept art:
The Morlok Frostbite is a unique, cryo-based pistol that won’t be obtainable anywhere else at launch. Forged by Morlok engineers, this Pistol packs enough force to take a target off their feet, and combined with Morlok's LN2 rounds, you have plenty of time to pick your shots!
Deliver cryo damage, slowing and controlling enemies
Reward precision and crowd management
Stand as a permanent badge of participation for those who helped push the community over the line!
We’ll be tracking progress throughout Next Fest via zombieassault.com, so whether you’re playing solo or in a full squad, every undead you drop helps the entire community!
Key Information
Steam Next Fest: February 23rd - March 2nd (Steam Store Page here!)
Earn an exclusive Pistol at launch by helping complete the Global Kill Count Challenge running throughout! (Track progress via zombieassault.com)
Play with the devs! We will also have some of the ZA:R devs looking to squad-up throughout Next Fest, so be sure to join our Discord (discord.gg/ninjakiwi) for further details on that when the time comes.
So get ready to gear up, dive in, and kill like it matters… because this time, it really does! Whether you’re a long-time Zombie Assault veteran or jumping in for the first time, we can’t wait for you to survive the onslaught with us. No questions this time as we’ve gone on for long enough, so get your questions in for next time!
Until then; stay alert, Mercs!
“Extraction isn’t optional” - Anonymous Merc #96
Original post
12 Dec 2025Developer post
[ SAS INTERNAL COMMUNICATIONS - SECURE ] >>
We’ve been going through the old files on Kurios station, and we’ve found references to a weapons cache the old Government had hidden away in case of emergency. How a zombie outbreak across the system didn’t constitute enough of a situation to crack it open, yet destroying an ent
24 Oct 2025Developer post
[ SAS EMERGENCY TRANSMISSION - SAON ]
Requesting immediate support! Some sort of rift has opened up here on Saon and what can only be described as a giant monster has stepped out of it! It’s massive and is just shrugging off any attacks against it. We Need Help! What’s worse is that zombies are also pouring out of th
09 Aug 2025Developer post
Despite the setbacks, our mission is unchanged.
>> Thank you for your assistance in our research. Your help is greatly appreciated and the compensation we have provided doesn't begin to match the sacrifice you and your fellow agents have made for the U.S.I. It appears that the team we sent for the Montano Seed were unsuc
04 Aug 2025Developer post
Zombie Assault: Resurgence - Dev Diary #8: Playtest Announcement!
Hey mercs! We’re back with another update on Zombie Assault: Resurgence, and we’ve got something very exciting to share… the next public playtest is just around the corner! We know you’ve all been itching to get your hands on the game again, and we feel like we’re now at the stag
Hey mercs!
We’re back with another update on Zombie Assault: Resurgence, and we’ve got something very exciting to share… the next public playtest is just around the corner! We know you’ve all been itching to get your hands on the game again, and we feel like we’re now at the stage where it’s time to get more of your extremely valuable feedback. So, without further ado, here are the details:
Playtest Timings
WHEN:
The playtest will begin at 10am on August 13th (BST) and run until August 18th (BST)
WHERE:
Steam - now using the Steam Playtest feature (full details below)!
What To Expect
It has (somehow!) been over 7 months since the first-look playtest, and since then, we’ve been hard at work! Your feedback so far has helped us push forward on the systems, features, and visuals that will bring ZA:R to life, so here’s some of what you’ve got to look forward to for this round of testing:
Drop in to Merc HQ in the all-new multiplayer HUB!
All 3 character classes can now be levelled up to rank 10
3 epic maps
Mining Facility, Icefield, and Abandoned Colony
4 Operation types
Eradication, Eradication Surge, Cache Recovery, and Close the Breach
Tough Mode
A modifier that increases difficulty but also increases rewards
Varied endings for Operations
Simple, Rush, and Boss
Strongboxes are back!
These will drop common guns and gear that can be equipped to your characters
The playtest build will include 10 guns, including starter weapons and a full HVM armour set
3 Abilities can be unlocked (final one at rank 10)
Skill Points gained on level up
Skill Points can be placed into Core and Class Skills
The ability to change equipment on your merc and have multiple saved loadouts
Canned chat
We will also have some of the awesome NK devs jumping in to join the zombie slaying action throughout the testing window, so we’ll post further details on that in our Discord at the time! Also, here’s a little sneak peek at a screenshot from the upcoming playtest build:
Your Feedback Matters
This playtest will help us zero in on some key system designs before we move into deeper content and polish work. Your feedback here is crucial, so here are a few specifics we’d love to get your thoughts on:
The overall look, feel, and difficulty of the game
Merc HQ performance (especially when there are multiple players in there)
Gun feel (pros and cons of the various weapons)
Feedback on initial skills
The last time we opened the game up to you all, we were blown away by the feedback and general community discussion, so please join our Discord here if you haven’t already to give us your feedback in real-time throughout the testing window, and keep an eye out for a feedback form that we’ll share near the end of the playtest.
How to join using Steam Playtest!
We’re now using Steam’s Playtest feature to make it easier than ever to hop into the action. Here’s how to join:
Head over to the Zombie Assault: Resurgence Steam page here!
Scroll down to the “Request Access” button under the “Join the Zombie Assault: Resurgence Playtest” section and click it.
Steam will notify you when you’ve been granted access - no keys needed!
Once access is granted, you’ll be able to install the playtest build straight from your library.
NOTE: If you took part in the last playtest, you still need to follow these steps to be included in this one
Make sure Steam notifications are enabled so you’re notified as soon as the build goes live, and whilst you’re there, be sure to add Zombie Assault: Resurgence to your Wishlist!
Questions from the comments
Q: Will bosses eventually have unique mechanics (phases, environmental hazards, etc)? Will there be more than one boss per map or randomized boss encounters?
A: To answer your first question: Yes! These are all things we’re looking to include in boss encounters. Secondly, Operations can feature randomized boss encounters, while Story missions will be a bit more intentional with any such fights.
Q: Will there be mastery ranks, prestige systems, or something to grind for post-cap? Will players be able to freely respec skills or loadouts later on?
A: We have lots of fun ideas planned for late-game systems, but for now we’re concentrating on fleshing out the main game feel. Loadouts can be changed as freely as you like. Skills can also be respec’d easily, but will come with an in-game currency cost.
Q: Will cosmetics (gun skins, armor variants, etc) be earnable or only monetized? Any plans for visual customization tied to class progression?
A: Cosmetics are likely to be a mix of earnable through playing the game and monetized. We are indeed planning on some changes to your appearance tied to class progression!
Q: Will bosses have a visible health bar or phase indicator to help players track progress during fights?
A: We will have health bars for bosses as well as clear visual feedback for changes in phases. Maybe not in the playtest, but they will be in the final game!
Q: How much of the game is singleplayer-friendly? Will there be a lot of content that's exclusively multiplayer or only balanced around multiplayer?
A: The game is being built in such a way that it will be equally playable in multiplayer as it is in single player, so you can choose to slay zombies solo or squad up!
That’s all for this dev diary! The countdown is officially on for the playtest, and we’re so excited for you all to get your hands on the game again. For now, why not whet your appetite by taking part in the latest SAS 4 Global Event starting now for extra juicy rewards!
Until then; stay alert, mercs!
“The undead are coming home, and they’re bringing all hell with them” - Anonymous Merc #75
Original post
30 Jul 2025Developer post
Do Your Part! Final Milestone!
>> Your work against the zombies is amazing. We couldn't wish for greater partners in these tests. This has confirmed that somehow the zombie populations are being reinforced. Their numbers drop significantly, yet over time we see them climb again. This seems to be only tru
09 Jun 2025Developer post
Mission Complete!
>> Despite our heavy losses, Kurios is ours and our technicians are currently ripping COMBOT’s influence out of the remaining systems onboard. USI intelligence has been in contact too. This push against the AI has been a major victory. Its presence in the Mobius sector is s
27 May 2025Developer post
Take Back Thrace! Fourth Milestone Achieved!
Abandoned in the Thrace System, SAS soldiers launch an offensive to secure a safe haven. All SAS soldiers must work together to reach the milestones and reap the rewards. All mission types contribute toward the goal. >> Ignore those messages. Combot is running scared. I did
13 Nov 2024Developer post
Zombie Assault: Resurgence - Dev Diary #1 & First Look Playtest!
Dev Diary #1 Welcome to our first dev diary for Zombie Assault: Resurgence! Since we announced the game, it has been amazing for the team to see the excitement build around the community and we can’t wait to show you more of what we’ve been working on over the coming months. As t
23 Oct 2024Developer post
New Game Announcement - Zombie Assault: Resurgence
We are extremely excited to announce our new game - Zombie Assault: Resurgence - a twin stick horde shooter with RPG elements coming to mobile and PC in 2025! Set 100 years after the events of SAS: Zombie Assault 4, the Thrace system was lost to zombies and the SAS is no more. Th
20 Sep 2022Developer post
SAS 4 Update 2.0 is rolling out now - Update Notes!
The long-awaited SAS 4 update has finally arrived and it's time to hit the road! An all-new level is waiting on the planet of Montano. Jump into the driver’s seat of one of the brand new cars and battle through the abandoned streets fighting hordes of zombies and the new gun-toti
The long-awaited SAS 4 update has finally arrived and it's time to hit the road! An all-new level is waiting on the planet of Montano.
Jump into the driver’s seat of one of the brand new cars and battle through the abandoned streets fighting hordes of zombies and the new gun-toting Scavenger enemies. Race to retrieve a mysterious artefact from space. Let's roll out!
New Content

New Map: Recovery - Available in both normal and nightmare difficulty. - Also supports Live Events (Apocalypse / Last Man Standing / Virus Samples). - Added 5 new achievements.
Bug Fixes & Balance Changes

Made improvements to the Faction War join flow to reduce the number of players receiving an error when trying to join a war.
Fixed the Zero Casualties Achievement not being possible.
Fixed a crash when leaving the coop screen.
Various performance & stability improvements.
Let us know your feedback in the comments below and happy gaming! :D
Original post
28 Apr 2022Developer post
SAS 4 Update 1.11 is out now!
New Content New faction war events will contain 2 new possible game modes: - Power Up: This facility is suffering major power issues. Morlok’s willing to pay to keep the emergency generators online while technicians offworld try to get the power back on. Be warned, the zombies se
New Content

New faction war events will contain 2 new possible game modes: - Power Up: This facility is suffering major power issues. Morlok’s willing to pay to keep the emergency generators online while technicians offworld try to get the power back on. Be warned, the zombies seem to be destroying any they find. If they destroy too many, we lose the facility. - Reactor Leak: This facility was conducting tests on the infection. Morlok wants that data but the reactor is in meltdown. Upload the data from as many terminals as you can. They should heal you a little when you activate them.
Bug Fixes & Balance Changes

Fixed bug where direct damage to bosses was being reduced by 50%.
Weapons that deal direct damage will now deal 100% damage to bosses.
Weapons that deal damage over time (e.g. Stripper, Krakatoa, etc) continue to do the same damage as 1.10.2
To be clear this isn't a nerf to damage over time but a buff to the other weapons.
Reduced Boss HP For Low Level Teams
Fixed Elite Augment Cores not giving enough damage, pierce and damage over time.
Fixed Biosynthesis healing per bullet instead of per zombie death
Fixed damage over time not applying to stunned zombies
Fixed bosses not having temporary immunity to stun after recovering from it
Fixed Adrenaline Skill granting a higher fire speed increase than intended.
Fixed crash on Power Out level
Changed Power Out to allow other types of bosses on Nightmare mode rather than being limited to Savage Mech.
Reduced Krakatoa base damage from 900 to 700
Fixed bug where high damage ammo bonuses were being applied twice to Krakatoa
Fixed bug where Krakatoa would spawn a lava pool per zombie hit rather than per shot.
Added a toggle to the settings screen and pause menu so players can disable screen shake.
Updated the timing for contracts so there should always be at least 1 contract available to play.
We have made improvements to the way we handle loot drops to reduce the chance of loot becoming stuck in areas players couldn’t access. Loot that spawns in areas only accessible by zombies will now be pushed out towards the player.
Fixed a bug where players would gain 1 clip size despite not having any bonuses to clip size.
Fixed bug where Zerfallen and Handekannone could not benefit from faction war clip size bonuses
Faction War Egg Hunt will now spawn zombies after 15s (down from 30s)
Faction War Elimination will now display your kill total during the game.
Fixed missing visuals in the Vaccine arena map for events that would make it look like you could walk through/over the walls.
Fixed some incorrect text in the gun mod expert description.
Various performance improvements.
Let us know your thoughts in the comments and happy gaming!
Original post
16 Oct 2017Developer post
SAS: Zombie Assault 4 is now available on Steam!
Hello all, Welcome to the Steam version of SAS: Zombie Assault 4! If you've played this game on mobile, you'll know what it's all about. If not (why not?!), check out the Store page here to watch the trailer and get filled in on the zombie-slaying goodness coming your way. If you
16 Oct 2017Developer post
SAS: Zombie Assault 4 is now available on Steam!
Hello all, Welcome to the Steam version of SAS: Zombie Assault 4! If you've played this game on mobile, you'll know what it's all about. If not (why not?!), check out the Store page here to watch the trailer and get filled in on the zombie-slaying goodness coming your way. If you