Saber Interactive's four-player co-op shooter runs on the Swarm Engine, which pours hundreds of zombies down stairwells and lets them climb over each other into living ramps. The Aftermath release of 21 September 2021 folded in first-person mode, the Vanguard class and two extra episodes set in Rome and Kamchatka. Eight classes, a three-tier weapon system and difficulty steps that run up through Extreme, Insane and Extinction sit on top of missions that take roughly 25 to 40 minutes each.
This walkthrough takes you from your first session to endgame content. Each phase has specific goals, priorities, and milestones. New to the game? Start with our beginner's guide first.
Quick Progression Summary
| Phase | Area | Focus | Role | Duration |
|---|---|---|---|---|
| 1. Start | New York | Swarm Engine zombie pyramids basics | Hellraiser | 1-2 hours |
| 2. Early | Jerusalem | Eight classes with perk trees mastery | Hellraiser | 3-5 hours |
| 3. Mid | Moscow | Weapon tiers and Advanced User + gear | Gunslinger or Hellraiser | 5-10 hours |
| 4. Late | Tokyo | Build optimization | Gunslinger | 5-10 hours |
| 5. Endgame | Rome | Min-max | Gunslinger or Vanguard | Ongoing |
See our maps guide for detailed area breakdowns.
Phase 1: Getting Started (New York)
The opening episode, running through Manhattan streets, a subway and an apartment block toward a rooftop evacuation. Sightlines flip between long avenues and cramped stairwells, which makes it the best place to learn how pyramids form.
Level/Difficulty: Any difficulty, comfortable from class level 1 Key Rewards: Early weapon unlocks, first class levels, safe practice against Bulls and Lurkers
What to Do in New York
- Learn Swarm Engine zombie pyramids. The engine tracks hundreds of zombies at once and lets them stack into ramps that reach balconies and rooftops within seconds. Spend your first session getting comfortable with this.
- Pick Hellraiser as your starting role. See our builds guide for why.
- Aim at the bottom of a climbing pyramid rather than the zombies already at the top. Removing three or four bodies at the base drops everything above them, while headshots on the upper layer just get replaced by the next climber.
- Acquire your first weapons upgrade: Keris V10 Advanced SMG or whatever's available.
- Clear all main content before moving on.
Phase 1 Checklist
- Understand Swarm Engine zombie pyramids fundamentals
- Hellraiser selected and functional
- New York main content cleared
- Ready for Jerusalem
Phase 2: Early Game (Jerusalem)
Rooftops, market alleys and a long descent through the old city, with more open ground than New York offers. Zombies pour over low walls from several directions at once, so fortifications need to face outward rather than down one lane.
Level/Difficulty: Recommended class level 5 and up Key Rewards: Sniper and battle rifle practice, wide fortification positions, high special zombie density
What to Do in Jerusalem
- Work on Eight classes with perk trees. Gunslinger, Hellraiser, Slasher, Medic, Fixer, Exterminator, Dronemaster and Vanguard each hold a separate progression track. This system becomes critical from here on.
- Farm for Keris V10 Advanced SMG if you haven't already. It's the key upgrade for this phase.
- Learn the audio cues before the visuals. A Screamer's shriek, a Bull's roar and the wet click of a Lurker all arrive before the model does, and calling the type out loud lets whoever has the shotgun turn to face it.
- Complete all objectives before pushing to Moscow.
- Consider whether Gunslinger might suit your playstyle better than Hellraiser.
Phase 2 Checklist
- Eight classes with perk trees integrated into gameplay
- Keris V10 Advanced SMG acquired
- Jerusalem fully cleared
- Ready for Moscow
Phase 3: Mid Game (Moscow)
Snowbound streets, an underground metro section and a set of interior holds with very short sightlines. Shotguns and submachine guns outperform rifles here, and Screamers hidden in the metro tunnels punish sloppy pushes.
Level/Difficulty: Recommended class level 10 and up Key Rewards: Close-quarters weapon experience, tight defence phases, heavy Lurker spawns
What to Do in Moscow
- Master Weapon tiers and Advanced User. Guns run from Tier 1 starters such as the Gal 9 Compact SMG up to Tier 3 pieces like the Keris V10 and HW416, with heavy weapons in a bracket of their own. This unlocks a new layer of gameplay.
- Start working toward ARK-103 Assault Rifle. It's the best weapon and becomes accessible around now.
- Kill Gasbags at range and never in a doorway your team has to walk through. The poison cloud lingers long enough to strip most of a health bar from anyone who pushes into it.
- This area is the main skill check. If you can clear it, you're ready for late game.
- Start investing in Defence phase fortifications for the tactical depth you'll need going forward.
Phase 3 Checklist
- Weapon tiers and Advanced User mastered
- ARK-103 Assault Rifle acquired or in progress
- Moscow fully cleared
- Ready for Tokyo
Phase 4: Late Game (Tokyo)
Dense urban blocks and interiors where the horde reaches you from stairwells and windows simultaneously. Fire builds shine because the corridors are narrow enough that a single Molotov blocks an entire approach.
Level/Difficulty: Recommended class level 15 and up Key Rewards: Exterminator and Slasher progression, vertical fights, Gasbag-heavy encounters
What to Do in Tokyo
- Finalize your build. You should be running Gunslinger or Hellraiser with optimized gear.
- ARK-103 Assault Rifle should be your primary. If you don't have it yet, prioritize getting it.
- Bring a Fixer to any Extreme or Insane run. Ammunition, not damage, is what ends those attempts, and the class turns a squad that runs dry midway through the final hold into one that keeps shooting.
- Special zombie roster optimization starts here. Small improvements compound into massive advantages.
- Farm this area for the resources needed to push into Rome.
Phase 4 Checklist
- Build fully optimized
- ARK-103 Assault Rifle upgraded to max
- Tokyo fully cleared
- Ready for Rome
Phase 5: Endgame (Rome)
Added with Aftermath, this episode ends in a last stand around Vatican City with some of the largest single swarms in the game. Ammunition management decides the run, which is why a Fixer is close to mandatory on the higher difficulties.
Level/Difficulty: Recommended class level 20 and up Key Rewards: Aftermath-only progression, Vanguard shield practice, the largest defence phase in the campaign
What to Do in Rome
- Rome tests everything. Come prepared with your best build and gear.
- Spend fortification placements on the two widest approaches instead of covering every slot. Barbed wire on a narrow corridor that already funnels enemies is wasted, while an electric fence on an open plaza buys the team ten seconds.
- The endgame loop: run Rome, optimize gear, push harder content.
- Experiment with Vanguard for a fresh take once you've mastered the standard builds.
- This is where Special zombie roster mastery separates good players from great ones. See our tips guide for advanced strategies.
Phase 5 Checklist
- Endgame content on farm
- Best-in-slot gear acquired
- Rome fully cleared
- Ready for challenge content
Common Progression Mistakes
- Shooting the top of a horde pyramid instead of the bodies holding it up, so the stack keeps rebuilding faster than you can clear it.
- Jumping into Extreme or Insane at low class level, before the perk columns that carry those difficulties are unlocked.
- Killing a Gasbag next to the team and blanketing the only exit in poison gas.
- Emptying the heavy weapon into ordinary zombies and having nothing left when the Bull charges the defence position.
- Placing fortifications in every available slot rather than concentrating them on the two lanes the swarm actually uses.
Key Tips for Smooth Progression
- Aim at the bottom of a climbing pyramid rather than the zombies already at the top. Removing three or four bodies at the base drops everything above them, while headshots on the upper layer just get replaced by the next climber.
- Learn the audio cues before the visuals. A Screamer's shriek, a Bull's roar and the wet click of a Lurker all arrive before the model does, and calling the type out loud lets whoever has the shotgun turn to face it.
- Kill Gasbags at range and never in a doorway your team has to walk through. The poison cloud lingers long enough to strip most of a health bar from anyone who pushes into it.
- Bring a Fixer to any Extreme or Insane run. Ammunition, not damage, is what ends those attempts, and the class turns a squad that runs dry midway through the final hold into one that keeps shooting.
- Spend fortification placements on the two widest approaches instead of covering every slot. Barbed wire on a narrow corridor that already funnels enemies is wasted, while an electric fence on an open plaza buys the team ten seconds.
For more advanced strategies, see our tips & tricks guide.
More World War Z Guides
- World War Z World War Z Overview
- World War Z Best Builds
- World War Z Tier List
- World War Z Beginner's Guide
- World War Z Tips & Tricks
- World War Z Weapons Guide
- World War Z Combat Guide
- World War Z Boss Guide
- World War Z Maps & Locations
- World War Z Crafting Guide
- World War Z Classes & Characters
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