Numantian Games left Early Access on 18 June 2019 with The New Empire, a 48 mission campaign carrying more than 60 hours on top of the existing Survival mode. The custom engine pushes up to 20,000 infected on screen at once, and a single one reaching an unwalled house can end a four hour colony in about 90 seconds. Everything hinges on wall placement, noise discipline and the score factor you set before the map generates.
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 | Build | Duration |
|---|---|---|---|---|
| 1. Start | The Deep Forest | One infected can end a run basics | Soldier | 1-2 hours |
| 2. Early | The Dark Moorland | Noise attracts the horde mastery | Soldier | 3-5 hours |
| 3. Mid | The Peaceful Lowlands | Score factor sets difficulty and reward + gear | Ranger or Soldier | 5-10 hours |
| 4. Late | The Frozen Highlands | Build optimization | Ranger | 5-10 hours |
| 5. Endgame | Caustic Lands | Min-max | Ranger or Titan | Ongoing |
See our maps guide for detailed area breakdowns.
Phase 1: Getting Started (The Deep Forest)
The starting Survival map, available immediately. Plenty of pockets and natural choke points, and no special infected anywhere on the map, which makes it the place to learn wall economy.
Level/Difficulty: Available from the start Key Rewards: Safe learning ground, forest chokes, unlocks Dark Moorland at 20 percent
What to Do in The Deep Forest
- Learn One infected can end a run. Infection spreads building to building. Spend your first session getting comfortable with this.
- Pick Soldier as your starting build. See our builds guide for why.
- Use the pause key as a core mechanic, not an emergency button. The game is built around pausing to issue orders, and no amount of mechanical speed will replace stopping the clock during a wave to retarget six units individually.
- Acquire your first equipment upgrade: Stone Wall or whatever's available.
- Clear all main content before moving on.
Phase 1 Checklist
- Understand One infected can end a run fundamentals
- Soldier selected and functional
- The Deep Forest main content cleared
- Ready for The Dark Moorland
Phase 2: Early Game (The Dark Moorland)
Gorges and rivers carve the terrain into narrow lanes, so fortification is cheaper than it looks. This is the first map that introduces special and giant infected.
Level/Difficulty: Unlocks at 20 percent score factor Key Rewards: Cheap terrain chokes, first special infected experience, unlocks Peaceful Lowlands at 40 percent
What to Do in The Dark Moorland
- Work on Noise attracts the horde. Every action has a noise radius. This system becomes critical from here on.
- Farm for Stone Wall if you haven't already. It's the key upgrade for this phase.
- Scout with exactly one Ranger. Sending a pair doubles the noise footprint for no extra map coverage, and one Ranger can outrun almost everything on the map if it wakes something it should not have.
- Complete all objectives before pushing to The Peaceful Lowlands.
- Consider whether Ranger might suit your playstyle better than Soldier.
Phase 2 Checklist
- Noise attracts the horde integrated into gameplay
- Stone Wall acquired
- The Dark Moorland fully cleared
- Ready for The Peaceful Lowlands
Phase 3: Mid Game (The Peaceful Lowlands)
The name is a lie. Wide open terrain means enormous wall spending, large lakes block a fifth to two fifths of the buildable area, and multiple Villages of Doom threaten from different directions at once.
Level/Difficulty: Unlocks at 40 percent score factor Key Rewards: High resource ceiling, multi-front defence practice, unlocks Frozen Highlands at 60 percent
What to Do in The Peaceful Lowlands
- Master Score factor sets difficulty and reward. Before generating a Survival map you set swarm size, map type and duration, and the game converts those into a percentage score factor. This unlocks a new layer of gameplay.
- Start working toward Wooden Wall. It's the best equipment and becomes accessible around now.
- Identify the two or three chokes the map gives you before day 15 and commit everything to them. Colonies fail because they wall a large perimeter thinly rather than a small one properly.
- This area is the main skill check. If you can clear it, you're ready for late game.
- Start investing in Villages of Doom seeded on the map for the tactical depth you'll need going forward.
Phase 3 Checklist
- Score factor sets difficulty and reward mastered
- Wooden Wall acquired or in progress
- The Peaceful Lowlands fully cleared
- Ready for The Frozen Highlands
Phase 4: Late Game (The Frozen Highlands)
Cold changes the maths rather than the enemy. Buildings burn extra energy staying warm and units move more slowly, though the infected are less aggressive to compensate.
Level/Difficulty: Unlocks at 60 percent score factor Key Rewards: Energy management practice, slower waves, unlocks Desolated Wasteland at 80 percent
What to Do in The Frozen Highlands
- Finalize your build. You should be running Ranger or Soldier with optimized gear.
- Wooden Wall should be your primary. If you don't have it yet, prioritize getting it.
- Convert wooden walls to stone before the wave that first includes specials. Wood buys you the opening third of the run, and rebuilding under pressure costs more stone than upgrading calmly ever would.
- Tesla Tower energy grid optimization starts here. Small improvements compound into massive advantages.
- Farm this area for the resources needed to push into Caustic Lands.
Phase 4 Checklist
- Build fully optimized
- Wooden Wall upgraded to max
- The Frozen Highlands fully cleared
- Ready for Caustic Lands
Phase 5: Endgame (Caustic Lands)
The final Survival map and the hardest score modifier, with the densest special infected population and one giant Doom Village. It tends to generate with more chokes, which is the only mercy it offers.
Level/Difficulty: Unlocks at 100 percent score factor Key Rewards: Highest score multipliers, dense special infected, the top of the Survival ladder
What to Do in Caustic Lands
- Caustic Lands tests everything. Come prepared with your best build and gear.
- Place every Tesla Tower well inside the perimeter. Defensive buildings need power, so a tower destroyed on the edge silences an entire section of wall at the exact moment it matters most.
- The endgame loop: run Caustic Lands, optimize gear, push harder content.
- Experiment with Titan for a fresh take once you've mastered the standard builds.
- This is where Tesla Tower energy grid 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
- Caustic Lands fully cleared
- Ready for challenge content
Common Progression Mistakes
- Walling the entire buildable area thinly instead of sealing two chokes properly, which leaves nothing to spend on towers.
- Firing on a wandering group with Soldiers near a Village of Doom and pulling the whole village into a colony with wooden walls.
- Placing Tesla Towers near the perimeter, so the first breach depowers a whole bank of Ballistas and Shocking Towers.
- Expanding housing for gold income without expanding food and energy first, then watching the colony stall at negative income.
- Treating the final wave like the previous ones. It arrives from every direction, so a colony fortified on two sides only is already lost when the timer starts.
Key Tips for Smooth Progression
- Use the pause key as a core mechanic, not an emergency button. The game is built around pausing to issue orders, and no amount of mechanical speed will replace stopping the clock during a wave to retarget six units individually.
- Scout with exactly one Ranger. Sending a pair doubles the noise footprint for no extra map coverage, and one Ranger can outrun almost everything on the map if it wakes something it should not have.
- Identify the two or three chokes the map gives you before day 15 and commit everything to them. Colonies fail because they wall a large perimeter thinly rather than a small one properly.
- Convert wooden walls to stone before the wave that first includes specials. Wood buys you the opening third of the run, and rebuilding under pressure costs more stone than upgrading calmly ever would.
- Place every Tesla Tower well inside the perimeter. Defensive buildings need power, so a tower destroyed on the edge silences an entire section of wall at the exact moment it matters most.
For more advanced strategies, see our tips & tricks guide.
More They Are Billions Guides
- They Are Billions They Are Billions Overview
- They Are Billions Best Builds
- They Are Billions Tier List
- They Are Billions Beginner's Guide
- They Are Billions Tips & Tricks
- They Are Billions Weapons Guide
- They Are Billions Combat Guide
- They Are Billions Boss Guide
- They Are Billions Maps & Locations
- They Are Billions Crafting Guide
- They Are Billions Classes & Characters
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