World & Progression

Biome order, game stage, misery scaling, POI risk, events, and getting around

Biome difficulty runs differently

In Rebirth the Burnt Forest is the hardest biome, not the easiest. The order is Forest → Desert → Snow → Wasteland → Burnt Forest. Loot improves in step:

Each biome applies a percentage first and then adds a flat number of points. A base game stage of 60 becomes 96 the moment you step into the Desert: 60 raised by 10%, plus 30. (An earlier version of this guide, working from a December 2024 video, described this as "+10, then +30%", which the game files don't support.) POI tier then raises or lowers it further, and game stage reduction armor mods lower it. On horde nights only the flat bonus is added before the horde scaling.

What shows up, and when

Bandit class score. Each class adds (its level, capped at 10, divided by 10) squared, times 10. Bandit events need a score of 2.3, and tougher bandit tiers start at 3.4, 4.7 and 6.2. With one class that's roughly class level 5, 6, 7 and 8. Spreading levels over several classes counts for less than putting them in one.

Misery: the zombies level up with you

Three systems scale the zombies as you get stronger. Because player levels give no perk points, raising the XP multiplier only makes the game harder.

• Ascension (ten ranks, one per ten player levels): a spawning zombie rolls for upgrades, with about a 50% chance per roll at every rank; what it can roll widens as the rank goes up. Speed bursts (2.5% faster per rank; ferals don't get them), fire/shock immunity and elemental attacks from rank 3, opening doors from rank 4, 2-meter jumps at ranks 6 to 8, and 3-meter jumps from rank 9.
• Natural Selection (tied to your kill count): at milestones of 500, 1,250, 2,000, 3,500, 6,000, 9,000, 13,500, 18,000, 25,000, and 35,000 kills, zombies can gain more health, more damage, more speed, regeneration, or combinations. By default horde-night kills don't count.
• Rebirth (ten ranks, every 15 player levels from 15 to 150): each rank adds a 2.5% chance that a killed zombie gets back up, and a 7.5% chance that it evolves into a stronger version when it does. At the top rank, 25% revive, 75% of those evolve, and a zombie can rise up to four times (1, 2, 3, then 4 revives as the ranks go up). Never on horde night, and never for bosses.

Your kill count and level are shown on screen.

POI risk

The POI Risk setting (None, Low, Default, High: multipliers 0, 0.5, 1 and 1.5) raises the game stage inside a POI. The extra game stage is the POI's tier bonus (1, 30, 60, 90, 120 and 150 for tiers 0 to 5) plus a biome bonus (0, 20, 40, 60 and 80 from Forest to Wasteland), times the risk multiplier, shrinking as your own game stage rises toward 590. So a fresh character in a tier 5 Wasteland POI fights at about game stage 230 on Default: radiated zombies instead of beginner spawns. By game stage 590 the bonus is gone. Zombie placement inside POIs is also randomized, so a building won't play out the same way twice.

Events

• Boss events. From player level 8, a boss can turn up with about 10 minions and 2 support zombies (checked every minute, with a cooldown after each one). Boss tiers follow player level, see the table above. Zombie-animal bosses join from level 35.
• Seekers (level 30+) hunt you down, break things in their way, explode, and call in help. Wraiths join from level 50.
• Bandits need player level 10 and a class score of 2.3 (see above). Tougher bandit groups with leaders and ranged weapons come at higher class scores.
• Screamer nights are off by default. Switched on, they come every 4 to 5 days (Lower), 2 to 3 days (Default) or every night (Higher), from player level 20. Every 90 seconds at night there's a chance (your level divided by 225, 150 or 75) of another screamer, up to 6 within 150 blocks. This is separate from normal heat-driven screamers.
• Airdrops are contested. A crate takes 20 seconds to open. When you get within 10 blocks, defenders spawn; the crate has 2,000 to 6,000 health, and if you haven't opened it 10 minutes after they spawn, it explodes. Clear them out first.
• Horde night: three times the vanilla horde size by default, a quarter of the usual XP from horde kills, and a 70% loot-drop chance.
• Wandering hordes come at random sizes and intervals, with a 30% chance of a herd.
• Outbreaks are the mega-hordes: wandering hordes of about 50 to 100 zombies that keep coming for a while. (From play; the exact numbers aren't in the files.)
• Storms start after day 1, hour 12. Tornadoes only come on horde night, if switched on.

Biome hazards

How biomes hurt you depends on the scenario.

Normal play (no scenario, the default)

• Without protection, each biome gives you a grace timer: Desert 120 seconds, Snow 90, Wasteland 60, Burnt Forest 30 (Forest is safe). After that you lose 1 health every 2 seconds until you get to shelter, where the timer recovers.
• Biome badges protect you for good. With the default Biome Progression (jobs and loot) you earn them by doing jobs and looting in each biome.
• Consumables buy time: Charcoal Breather Rag (Burnt Forest), Cooling Gel Packs (Desert), Chemical Heat Packs (Snow) and Rad Purge Injector (Wasteland). Each adds 300 seconds of protection (up to 900) and a run-speed boost.
• Steroids protect you from storms.

The Purge scenario

• From player level 5, every 60 seconds outside the Forest you can catch infection, fatigue or dysentery, depending on the biome. A Vitamin blocks them. Riding a vehicle makes you immune.
• The four biome Stabilizer Devices are armor mods, and they stack up: the Snow stabilizer covers the Desert too, and so on. Each recipe unlocks once you've purged 75% of the previous biome (see Gear & Armor).
• There's no Blood Moon in the Purge (from play).
• The Hive scenario has no biome ailments.

Verified against the Rebirth 2.6 files and code.

Getting around

• Roads are faster. Gravel and asphalt give a 15% speed boost, to zombies as well.
• Vehicles are repaired, not just crafted. Repairable vehicles around the world need parts: spark plugs, starters, carburetors, fuel pumps, wheels, and the right engine. You'll also need a hotwire kit from the vending machines. You don't have to start with a bicycle.
• Wrench the same model. Once you've found a repairable vehicle you want, mark it and wrench every unrepairable one of the same kind you pass. They have a much higher chance of dropping the parts it needs.
• Vehicles climb a ladder from the minibike to a motorcycle, a 4x4, and a gyrocopter (each needs chassis, handlebar, and accessory schematics). Rebirth also adds a motocross bike, an armored buggy, and a helicopter.
• Gretta, the handywoman at Bob's compound in the Desert, sells vehicle parts, a 4x4, a motorcycle, and a helicopter.
• Honk to open trader gates. Ring your bike bell or honk your horn and the compound gate opens and closes behind you. This needs Bartering level 1.
• Generators on night missions can be salvaged for a repairable generator. It takes longer than a normal salvage, so you don't do it by accident mid-mission.

Caves

Rebirth ships with support for The Descent, a procedurally generated cave system, and has a Cave Spawns setting. This guide doesn't cover cave exploration in depth yet.

Global achievements

Account-wide milestones give lasting bonuses, such as more resources from wild animals and a bigger harvest from planted crops.

Settings worth knowing

Beyond the ones named above, the Rebirth settings include a game stage multiplier (scales biome, job, and horde game stage), POI risk and POI sense, feral sense, knockdown, zombie digging, whether zombies destroy areas, Horde Night Plus, a turbo mode, and wandering-horde size, frequency, and despawn.