Zero Sievert 2 expands the world of Zakov around the feature fans have asked for most: multiplayer co-op, alongside deeper lore, new systems, and an evolved 2.5D visual style. Together, squads of friends can push deeper into Zakov, turning the first game’s lonely one-more-run tension into shared moments of panic, questionable decisions, and hard-earned extractions.

Building on the high-stakes yet approachable core of the original; It expands the scale, story, systems, and presentation of the original, while introducing co-operative multiplayer, the most requested feature from the original’s dedicated community.

After your grandfather is gravely wounded, your search for answers pulls you into a wider struggle between the ruthless Zakov People’s Army, the shady Crimson Corporation, and the mysterious Church of the Grieving Star. Their motives might differ, but all of them fight over the same question: "How do you harness the power that made Zakov the Zone?" Across Zakov you will find that traders, factions, and other figures have problems of their own, and plenty of reasons to make them yours.

Hunt solo or with up to four players. Move together, cover more ground, and back each other up when things turn south. Every Hunter gains experience in co-op, keeps their own gear and loot, and can pursue their own quests during the same Hunt.

Zero Sievert 2 sends Hunters across new and returning maps, each with its own threats, landmarks, and opportunities. Each Hunt changes the layout, but fixed landmarks help you navigate, find loot, and spot danger early. Conditions can change a Hunt in an instant. Day turns to night. Fog rolls in. Blizzards cut visibility. Acid rain makes every minute outside riskier, and on some Hunts, special events can block routes, draw factions into open conflict, or pull you into fights you did not start.

Anomalies are one of Zakov’s defining threats, and Hunters learn quickly to test the path ahead with bolts before moving forward. They can be deadly, but they also leave behind crystals valuable enough to draw Hunters back into the Zone. Relics - new in Zero Sievert 2 - are powerful objects linked to those same anomalies. Hunters can equip them for passive bonuses, and the most powerful relics can even grant active abilities. Every use pushes a relic closer to destabilisation. Push one too far, and it can trigger a Catastrophic Failure.

Your Hunter develops through four skill paths: Combat, Survival, Recon, and Ingenuity. How you Hunt shapes that growth, so aggressive players develop differently from those who scout ahead and stay quiet. Weapon Mastery grows with each weapon class you use, while Map Mastery is earned on each map in Zakov.

More than 30 weapons can be modified and maintained for the Hunt. Whether you prefer pistols, shotguns, ARs, or long-range rifles, each type suits a different kind of Hunter. Adjust weapons to make them your own. Ammo choice matters: different rounds trade off penetration, damage, and cost. So build your perfect loadout to tackle any situation. But no matter how good your gun is: neglect it for too long and it might fail you. A jam at the worst possible moment will be fatal.

Return to Zero Sievert with loot, improve your space and prepare for the next Hunt. What starts as a makeshift hideout gradually becomes a base for the Hunts ahead. As your journey progresses, new traders and survivors arrive with fresh jobs and better equipment.

The original Zero Sievert began as a solo project built by Luca Carbonera in his bedroom. It went on to do what few one-person indie games manage: find a large audience, sell over 600,000 copies on Steam, and build a loyal community around its punishing survival loop that kept players coming back for “one more run”.

The Zero Sievert community helped make the sequel possible. From wishlists and reviews to Discord feedback, videos, guides, mods, and years of support, Zero Sievert grew because fans kept coming back to Zakov. Soon, they’ll be able to bring their friends with them.

Zero Sievert 2 is being developed by Underdog, a new London-based independent studio formed by former Splash Damage veterans, in partnership with Luca Carbonera of CABO Studio. Founded in 2025 by Giuseppe Navarria and Antoine Fion, Underdog brings that experience to the challenge fans have been asking for most: turning Zero Sievert’s tense solo extraction loop into co-op without losing what made it special.

“As a fellow Italian, I’m proud of what Luca achieved with Zero Sievert,” said Giuseppe Navarria, Co-Founder of Underdog. “He was one of the first to show how well extraction could work from a top-down perspective, keeping the tension, loot and risk, but stripping away some of the more toxic PvP-heavy edges of the genre.Zero Sievert 2 is our chance to honour that foundation, then let you bring your friends into the mix.”

For Luca Carbonera, seeing Zero Sievert grow from a solo personal project into a full co-op sequel still feels surreal.

“When I started in my bedroom as a solo indie dev with just an idea, I never in my wildest dreams imagined it would grow into this,” said Luca Carbonera, creator of Zero Sievert and founder of CABO Studio. “This sequel exists because fans believed in it and supported it. What matters to me now is that it still feels like Zero Sievert. Underdog understands what made the first game work, and they have the multiplayer experience to take it somewhere I could not have taken it alone.”

Underdog is backed by Paul Wedgwood, co-founder and former CEO of Splash Damage. His own studio journey began over 25 years ago in the late-90s PC modding scene, with a small bedroom team that grew into one of the UK’s best-known online shooter studios. For Wedgwood, the appeal is helping Underdog keep that early-stage hunger while avoiding some of the mistakes that often only become obvious later.

“The games industry has gone full circle,” said Paul Wedgwood, CEO of Modern Wolf and Executive Chairman of Underdog. “AAA will always matter, but at that scale it gets harder to take real creative risks. Right now, a lot of the most interesting work is coming from small teams again: people close to the game, close to the players, and willing to bet on ideas that would never survive a committee. That is what excites me about Underdog.”

Across Early Access, launch, and post-1.0 support, the Zero Sievert community has helped shape the game through feedback, bug reports, videos, mods, guides, and a steady conversation with the team. That same open development rhythm will continue as Zero Sievert 2 moves forward.

Zero Sievert 2 will be coming to Steam Early Access and will remain so for about 8 months, with major updates roughly every 2 months.

“Zero Sievert 2 will launch in Early Access with two fully playable locations, forming the first act of the game. These include NPCs, main quests, and optional content. You’ll be able to play both solo and in online co-op with up to 4 players. The game is currently in pre-alpha and not ready for release just yet. You can follow development through our dev diaries on YouTube and updates on Discord.

“For the full version we plan to significantly expand the game with more locations, more quests, and a wider range of weapons and loot. We'll also expand on the game's narrative, with a dramatic storyline that ties together the past of multiple characters.””

Key Features

• Co-op Extraction Gameplay Hunt solo or with up to four players, covering more ground, and supporting each other when things go wrong.
• Dynamic, Procedural World Explore the Zakov Exclusion Zone, with new and returning maps reshaping their layout each hunt.
• Expanded Progression Systems Develop your hunter across 4 distinct skill paths (Combat, Survival, Recon, and Ingenuity).
• Anomalies and Relics Anomalies are a constant threat to Hunters, requiring testing the path ahead with bolts before moving forward.
• Deep Weapon Customisation More than 30 weapons can be modified and maintained with attachments and jamming mechanics.
• Story and Factions A conflict between 3 competing factions: The Zakov People’s Army, Crimson Corporation and The Church of the Grieving Star.
• Base Progression Return from Hunts with loot, upgrade your hideout, and prepare for the next run.

Zero Sievert 2 is in development for PC (Steam / Epic Games Store), with consoles being considered.