ZERO Sievert presents The Rotking Update
Face the Rotking. Master the Chemicals. Survive the Zone.
This update brings some of the biggest additions yet to ZERO Sievert — new bosses, enemies, factions, perks, and gear — alongside dozens of quality-of-life improvements and fixes.
Face off against the Rotking, uncover chemical secrets beneath the Swamp, and encounter a new Industrial Faction with powerful, unique equipment.
All that, plus new ammunition types, perks, and smarter UI and sound systems make this update one of the most feature-packed yet.
Let’s dive in.
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💀 NEW MUTANTS & BOSSES
🧬 Rotfang
A new threat stalks the Zone. The Rotfang is a twisted mutant born from chemical corruption, bringing new challenges to deep-zone expeditions.
👑 Rotking
A terrifying new boss emerges from the sewers:
Wields a unique weapon and armor, both infused with chemical properties.
Armor Passive Effect: Standing on chemical anomalies restores HP.
Pairs perfectly with the new Chemical Grenade, offering deadly combat synergies.
💣 NEW WEAPONRY & GEAR
🧪 Chemical Grenade
A deadly new tool of chaos. On impact, it spawns temporary chemical anomalies on the ground, dealing area damage over time and opening up creative tactical options.
🧰 Rotking’s Loot & Questline
After completing “The Crystal”, a new quest — “Chemical Documents” — sends you back into the sewers to confront the Rotking.
Defeat him and recover critical intel to unlock the crafting recipe for Chemical Grenades.
⚙️ NEW FACTION: THE INDUSTRIALS
A powerful new end-game faction has appeared in the Industrial Area, unlocked after completing “The Bridge to Zakov.”
Speak to the Barman and select the new dialogue option, “Any news?”, to begin your involvement.
Faction Gear
Standard Faction Armor: 15% chance to deflect bullets — includes VFX and SFX.
Boss Armor: Deflected bullets heal 25% of their damage back to the wearer.
Unique Boss Weapon: A one-of-a-kind firearm wielded by the faction leader.
🔫 NEW AMMUNITION TYPES
5.45x39mm BP – Craftable, high-penetration rounds.
5.45x39mm Horizon – Exclusive to the new Horizon Boss.
7.62x25mm Chemical – Craftable after completing “Chemical Documents.” Dropped only by the Rotking.
🧠 NEW PERKS & BALANCE CHANGES
New Perks
Rolling Start (Pistols, SMGs, Shotguns): After standing still for 1 second, gain +30% movement speed for 2 seconds.
Point Blank (Pistols, SMGs, Shotguns): Shots inside effective range have a +20% armor penetration chance on full hits.
Sticky Fingers (Hunter): Find 5x more Roubles in loot.
Updated Perks
Grenade Expert: Now grants immunity to flash grenades and your own grenades.
Phantom Bullets (SMGs): Level requirement reduced from 15 → 11.
Point Blank: Adjusted behavior — now triggers on full hits instead of crosshair color indicator.
🧩 QUALITY OF LIFE IMPROVEMENTS
Ear Ring Volume Slider: Control the volume of grenade ringing effects separately.
Ammo Type Indicator: Easily see which ammo type your weapon is currently using.
Improved Item Tooltip: Now shows how many of that item you own in your bunker stash.
ESC Key Behavior: Consistently returns to the previous menu when navigating settings.
UI for Active Injectors: Cleaner, clearer visualization of currently active injectors.
Rain Sound Fix: Rain audio now correctly stops when the player moves indoors.
New Achievement: Steam achievement for completing the tutorial (unlocks automatically when
the extraction countdown reaches 0).
🏗️ QUESTS & WORLD CHANGES
New Quest – “Chemical Documents”: Introduces the Rotking boss and Chemical Grenade crafting.
New Quest – “Base Building”: Unlocks after “Valuable Item.” Tasked with constructing your first base module.
Swamp Sewer Rework: Major layout and lighting improvements for smoother navigation and stronger atmosphere.
New Extraction Point: Added a new extraction zone in the south-west area of the sewer.
🧱 FIXES & ADJUSTMENTS
Fixed barman text “Any news?” not displaying correctly.
Fixed crash on chemical anomaly interactions.
Fixed solid wall misalignment during the “Machinery” quest.
Fixed crash caused by player’s own flashbang.
Grenade Expert perk flashbang immunity now works correctly.
Shotgun Slug ammo no longer has a minimum effective range limit.
Fixed lighting issues in the sewer.
Fixed dialogue display issues after “Revelations.”
TSU Scope can now be mounted on the Wintar BK.
🌧️ LOCALIZATION
General localization fixes and improvements across menus, quests, and tooltips.
As always, your feedback helps shape ZERO Sievert.
Keep sharing your thoughts, builds, and stories with us — and we’ll see you in the Zone.
– The ZERO Sievert Dev Team