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.
They Are Billions features distinct areas with increasing difficulty. This guide covers every major location in progression order: what to do, what to get, and when to move on. For the step-by-step path, see our walkthrough.
Area Progression Order
| Order | Location | Difficulty | Key Rewards | Recommended Build |
|---|---|---|---|---|
| 1 | The Deep Forest | Available from the start | Safe learning ground, forest chokes, unlocks Dark Moorland at 20 percent | Soldier |
| 2 | The Dark Moorland | Unlocks at 20 percent score factor | Cheap terrain chokes, first special infected experience, unlocks Peaceful Lowlands at 40 percent | Soldier |
| 3 | The Peaceful Lowlands | Unlocks at 40 percent score factor | High resource ceiling, multi-front defence practice, unlocks Frozen Highlands at 60 percent | Ranger |
| 4 | The Frozen Highlands | Unlocks at 60 percent score factor | Energy management practice, slower waves, unlocks Desolated Wasteland at 80 percent | Ranger |
| 5 | Caustic Lands | Unlocks at 100 percent score factor | Highest score multipliers, dense special infected, the top of the Survival ladder | Ranger |
The Deep Forest: Starting Area
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.
| Attribute | Detail |
|---|---|
| Difficulty | Available from the start |
| Key Rewards | Safe learning ground, forest chokes, unlocks Dark Moorland at 20 percent |
| Recommended Build | Soldier |
| Key Equipment | Stone Wall |
What to Do Here
- Learn the basics of One infected can end a run. This is where you practice without heavy punishment.
- Collect starting resources and your first equipment upgrade.
- Clear all main content before moving to The Dark Moorland.
- If you're struggling, read our beginner's guide.
The Dark Moorland: Early Game
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.
| Attribute | Detail |
|---|---|
| Difficulty | Unlocks at 20 percent score factor |
| Key Rewards | Cheap terrain chokes, first special infected experience, unlocks Peaceful Lowlands at 40 percent |
| Recommended Build | Soldier |
| Key Equipment | Stone Wall |
What to Do Here
- Focus on mastering Noise attracts the horde. It's critical from this point on.
- Farm for Stone Wall if you don't have it yet.
- Complete all objectives for maximum rewards.
- Prepare for the difficulty spike in The Peaceful Lowlands.
The Peaceful Lowlands: Mid Game
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.
| Attribute | Detail |
|---|---|
| Difficulty | Unlocks at 40 percent score factor |
| Key Rewards | High resource ceiling, multi-front defence practice, unlocks Frozen Highlands at 60 percent |
| Recommended Build | Ranger |
| Key Equipment | Stone Wall |
What to Do Here
- This is the main skill check. Bring an optimized build.
- Wooden Wall becomes accessible here. Prioritize getting it.
- Master Score factor sets difficulty and reward for the boss encounters.
- Check our boss guide if you get stuck.
The Frozen Highlands: Late Game
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.
| Attribute | Detail |
|---|---|
| Difficulty | Unlocks at 60 percent score factor |
| Key Rewards | Energy management practice, slower waves, unlocks Desolated Wasteland at 80 percent |
| Recommended Build | Ranger |
| Key Equipment | Wooden Wall |
What to Do Here
- Full build optimization is expected by this point.
- Wooden Wall should be your primary, fully upgraded.
- Tesla Tower energy grid mastery starts mattering here.
- Farm resources for the push into Caustic Lands.
Caustic Lands: Endgame
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.
| Attribute | Detail |
|---|---|
| Difficulty | Unlocks at 100 percent score factor |
| Key Rewards | Highest score multipliers, dense special infected, the top of the Survival ladder |
| Recommended Build | Ranger |
| Key Equipment | Wooden Wall |
What to Do Here
- This is endgame. Best-in-slot gear and a perfected build are mandatory.
- See our boss guide for endgame fight strategies.
- The reward loop: clear content → upgrade → push harder content.
- Experiment with Titan for variety once you've mastered the meta.
Exploration Tips
- Clear areas in order: The Deep Forest → The Dark Moorland → The Peaceful Lowlands → The Frozen Highlands → Caustic Lands. Skipping areas means missing resources you'll need later.
- Check every corner: Hidden caches and secrets are often in non-obvious locations.
- Match your equipment: Some areas favor different equipment types.
- Read the walkthrough: Our walkthrough provides exact progression milestones for each area.
- Don't rush: Clearing an area fully gives more resources than speedrunning two areas.
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 Walkthrough
- 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 Crafting Guide
- They Are Billions Classes & Characters
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