They Are Billions is a steampunk strategy survival game developed by Numantian Games. This guide covers the base game: the PC full release, PlayStation 4 and Xbox One editions, and the current Nintendo Switch 2 edition. It does not cover the separate soundtrack and art book item as gameplay content.
Content warning: The game is rated Teen, with blood, violence, fantasy violence, blood and gore, and use of tobacco descriptors. This guide keeps those themes non-graphic and focuses on colony survival.
They Are Billions looks like a city builder until one infected slips into a house and turns a tidy neighborhood into a disaster. The safest way to learn it is to treat every decision as both economic and defensive: more tents mean more income, more territory means more resources, and every new edge of your colony must be watched. Use the pause button constantly, expand with purpose, and build defenses that buy time before a swarm reaches your workers.
Difficulty note: this guide starts with beginner fundamentals, but the game itself is demanding. A colony can fail because of an economic or perimeter mistake made well before the final swarm, so treat each loss as information for the next run.
Essential Tips
1. Pause Before Every Big Decision
They Are Billions is real-time strategy, but it is not asking you to win through frantic clicking. Pause before placing buildings, redirecting units, checking a wave warning, or deciding where the next Tesla Tower goes. A paused minute spent reading the map can prevent an hour of rebuilding.
Use pause to compare needs at the same time: food, workers, energy, gold income, wood, stone, iron, oil, and exposed borders. If a plan solves one shortage but opens two attack angles, it is not ready yet.
2. Build the Economy That Your Defenses Need
A bigger army and stronger walls come from a stable colony, not from panic buying. Dwellings bring colonists and income, food supports housing and units, workers staff buildings, and energy keeps the colony running through Tesla Towers, mills, and power plants. Resource buildings then turn nearby terrain into wood, stone, iron, oil, or food.
Do not expand just because an empty patch looks useful. Expand because the colony needs a specific resource and you already know how you will defend the new edge.
3. Scout Quietly and Keep Patrols Moving
Infected roam, listen, and react. Early on, your soldiers are your real defense because you cannot afford complete walls and towers everywhere. Place units where they can see approach routes, then use patrols to cover the gaps between buildings and terrain.
Scouting is still necessary. You need to find resources, chokepoints, and danger zones before they find you. Move carefully, avoid needless noisy fights near dense infected pockets, and pull units back before they drag trouble into your housing.
4. Expand Toward Chokepoints, Not Open Problems
The easiest land to build on is not always the safest land to own. A wide-open border asks for longer walls, more towers, more patrols, and more attention. A narrow pass or natural barrier can let a smaller force hold a much larger colony.
Before placing a new Tesla Tower, look past the resource you want. Ask where the final wall line will sit, which units can cover it, and whether future buildings will have enough room behind it. A good expansion should shorten the problem, not just grow the map.
5. Use Walls as Time, Not as Courage
Wood walls are available early, cheap, immune to infection, and useful because infected have to destroy them while your units fire over them. That makes walls one of your best early tools, but walls alone do not kill the swarm.
Put soldiers, towers, or other damage behind the wall. Leave repair access where possible. Use gates only where you need movement, and avoid long single-layer lines that fail everywhere once one section falls.
6. Stop Breaches Immediately
One infected inside a worker building is enough to create a chain reaction. Housing is especially dangerous because a breach can turn colonists into more infected, which then rush nearby buildings and multiply the emergency.
When the alarm hits, pause, identify the exact building or wall section, and send enough units to erase the infection fast. If the area is already collapsing, isolate it with a fallback line instead of feeding scattered units into the same opening.
7. Upgrade Basics Instead of Abandoning Them
Some production buildings can move from basic to advanced versions by paying the difference rather than wasting the whole original investment. That means early farms and quarries can still fit a long-term plan when their placement is good.
The lesson is not to spam buildings anywhere. It is to place early infrastructure carefully, with room for defenses and energy coverage, because a smart early economy can remain useful after upgrades unlock.
8. Plan Campaign Technology Before Spending
The New Empire campaign mixes colony missions, swarms, hero exploration, and a technology tree with many choices. Random spending can leave you feeling strong in one mission type and underprepared in the next.
Prioritize upgrades that improve repeatable fundamentals: economy, early defense, reliable soldiers, and tools that help multiple mission types. When a tech looks exciting but narrow, wait until you know which upcoming mission actually needs it.
9. Treat Survival Mode as Map Reading Practice
Survival maps are randomized, so a memorized route matters less than reading terrain and reacting well. Use them to practice opening scouting, resource evaluation, patrol placement, and wave preparation.
If a run fails, look for the first strategic mistake rather than the final swarm. Most losses begin earlier: a greedy expansion, an unscouted pocket, a weak wall line, or an economy that could not produce enough defense in time.
10. Respect Current Platform Differences
The PC game is the baseline for most advice. PlayStation 4 and Xbox One have the campaign, and the Nintendo Switch 2 edition currently advertises PC-equivalent content with Joy-Con 2 mouse support, USB mouse and keyboard support, and touch support.
That said, controls and small usability details can change by platform and patch. Keep strategy principles the same, but check your own control layout before relying on quick orders during a wave.
Economy and Expansion Priorities
Start by stabilizing the loop that keeps every other plan alive: housing for gold, food for colonists and units, workers for industry, energy for buildings, and wood for early construction. A shortage in any one of those can delay the wall, soldier, or tower you need when the next attack arrives.
Build outward in measured steps. A Tesla Tower is not just an economic tool; it is a commitment to defend more land. If a new Sawmill or Quarry forces you to guard a long open border, the resource may cost more than it produces. The best early expansions usually add a needed resource while creating a cleaner defensive perimeter.
Defense and Infection Control
Layered defense works better than a beautiful wall with nothing behind it. Patrol early, wall likely attack paths, place firing units where they can shoot over barriers, and use towers or stronger defenses when the economy can support them. Traps and heavier structures become more useful as swarms grow, but the principle stays the same: slow the infected, focus damage, and prevent contact with worker buildings.
During a crisis, pause first. Find the exact failure point, group enough force to solve it, and avoid spreading your army into little pieces. If a housing block starts turning, commit hard or create a fallback line. Half-measures usually give the infection more bodies.
Common Mistakes to Avoid
- Do not start a building spree without pausing to check food, workers, energy, and exposed borders - The shortage you ignore is usually the one that stops your defense.
- Do not send a noisy scout into dense infected territory and then retreat through your colony - The chase can bring danger straight to your houses.
- Do not place a Tesla Tower toward open land before deciding where the new wall line will go - Expansion without a perimeter creates more entrances for swarms.
- Do not rely on a wood wall with no units behind it - Walls buy time, but soldiers and towers do the killing.
- Do not leave houses near an active breach while you fight somewhere else - One infected worker can start a chain reaction through the block.
- Do not spend campaign technology points just because an upgrade looks powerful - Narrow upgrades can leave core economy or defense underbuilt.
- Do not build resource structures in awkward spots just to get a quick number increase - Bad placement can waste defensive space and complicate later upgrades.
- Do not ignore patrol routes after the first wall goes up - Small infected groups can still reach unfinished edges and quiet gaps.
- Do not keep expanding after a wave warning if your current perimeter is unfinished - Finish the defense before adding more land to protect.
- Do not chase the final swarm plan only at the end of the run - The last defense is built from every economic and territorial choice before it.
Summary
| Category | Top Tip |
|---|---|
| Pause | Stop time before building, fighting, or responding to wave warnings |
| Economy | Grow housing, food, workers, energy, and resources together |
| Scouting | Explore carefully and keep early patrols covering exposed paths |
| Expansion | Move toward useful resources and defendable chokepoints |
| Walls | Use barriers to delay infected while units fire safely behind them |
| Infection | Crush breaches immediately before worker buildings start cascading |
| Campaign | Spend technology on repeatable economy and defense value first |
| Platforms | Keep tactics stable, but check controls on your current version |
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8 checked for this guideEvery factual claim in this guide was checked against at least two independent sources before publication. These are the references used for They Are Billions.
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