They Are Billions – How to Win in 80 Days

I wanted to write down these notes to help players, who ask if their buildorder is wrong or if they play too slow. These are just standard values you dont have to follow exactly, but they will help you to understand the basics and win 100%+



  • Every wood spot 12+ is good, every stone spot 4+ is good. If you have such spots. Build a sawmill / quarry. 
  • Build fishing huts wherever you can, build hunting huts next to your sawmills. They get + from being next to wood and grasslands. 
  • Whenever you have free ressources, build more residential. There is no “enough buildings”. Between that never forget to build mills, always have some reserve power. 
  • Constantly build more troops. 
  • Constantly expand, if you feel you can survive it. Always expand to the next narrow spot that needs only small sections of walls to close up. 
  • Have 1 ballista on every wall. Dont upgrade to executioners before the final wave. They have much higher upkeep and will slow your progress down. 


  • Have at least 10 archers (5 if you know what you are doing) before you start expanding. Have 20-30 to clear the inner parts of the map completly. 
  • Dont build soldiers if you arent familiar with the units yet. They have huge damage but short range and attract zombies from a huge area. 
  • Always watch your troops! Dont let them run into their doom. 
  • Stay away from zombie buildings until you can take them down (if you ask yourself if you can take them down, you arent ready) 
  • Archers can only take 2 spitter hits. If a spitter attacks you, split your archer grp in two (or take the one targeted by the spitter, if you know what you are doing) and use one as bait and the other to take the spitter down. If your archers engange a spitter while you are not watching, you WILL lose them all! Always watch your troops! 
  • Dont run away from harpies. You only make it worse. 
  • Two towers behind a stone wall can stop a triggered zombie village from overwhelming you.


  • The inner parts of the maps are full of slow walkers. Kill them whenever you have the time. 
  • Always click on enemys in sight. Look out when runners start appearing between the walkers. 
  • Watch out for the zombies in black suits. If you arent behind a wall, 1-5 of them can seriously damage your archer grp. 
  • Beware of big fights. After getting more than 10 archers, constantly fighting zombies can attract runners from further away. Killing those will attract specials from even further away and you get into an endless loop that can only be broken by killing them all, dying, or falling back to a ballista / wall.

Day 1

  • Look if you have a 10+ wood spot in spawn range, if not, restart the map. 
  • Send out your archers in all directions. Scout until you run into zombies (dont aggro them pls), collect all ressources you can find. 
  • Take a look around and make a plan where you can implement effective defensive lines between trees, mountains and water

Day 2-5

  • Build fishing and hunting huts wherever there is space 
  • Build residential until you are at zero food 
  • Build another sawmill 
  • Build a quarry 
  • Build a mill before your energy reaches zero 
  • Build a soldier center

Day 5-10

  • Your gold income is between 200-400 
  • Continue building residential until your food reaches zero 
  • Build a wooden shop when you have enough ressources 
  • Research farm 
  • Research market when you have the ressources 
  • Research ballista if you dont feel safe 
  • Constantly build more archers 
  • Build more mills fishing and hunting huts wherever there is space you wont use for anything else 
  • Build farms wherever you have 50+ food or 40+ if you really need it 
  • Wall of all entrances

Day 10

  • Get ready for wave 1 
  • You can defend this wave with your archers, build a double wall if you feel unsafe 
  • Build a ballista if you were fast enough for the tech

Day 10-18

  • Your gold income is now 300-500 
  • Place down your market in the middle of your houses (I will teach you how to properly space your residential area at the end of this guide) 
  • Research wooden residential 
  • Continue building quarrys, mills, sawmills and food buildings 
  • Continue building more residential / start upgrading 
  • Research stone workshop if you have the ressources 
  • Continue building archers 
  • Build a ballista at each entrance 
  • Look at what you scouted at day 1 and deside in which direction you want to expand 
  • Take all your archers and start killing off all zombies into that direction, start building tesla towers behind you 
  • Stop expanding if you reach a new narrow entrance you can wall of easily 
  • Continue expanding whenever your archers idle. At this point never stop planing new expansions 
  • Research snipers when you have enough ressources 
  • Stop building archers, start building snipers

Day 18

  • Get ready for wave 2 
  • At this point you have enough archers (around 10-20) to defend the wave without towers 
  • You should have a ballista at each entrance, which could hold the wave alone (if double wall)

Day 18-26

  • Your gold income is 500-1000 
  • Get your stone workshop (or earlier if you were fast enough) 
  • Research bank 
  • Place down bank next to the market 
  • Place down a warehouse (look out where you place it, since it boosts nearby production). You need at least 2 warehouses at the end of the game. 
  • Since you now have enough gold income, start expanding like crazy. Place down sawmills at every 10+ and quarries at every 3+. Place down quarrys at every little piece of iron you can get. 
  • Research stone houses 
  • Research stone walls 
  • Research power plant if you dont have enough space for mills 
  • Build farms and huts everywhere 
  • Build mills everywhere 
  • Build / upgrade more residential 
  • Build more snipers, send them with your archers and put them on “target highest”, kill the special zombies you will now surely meet 
  • Research foundry if you have ressources ready

Day 26

  • Get ready for wave 3 
  • You now have archers and snipers 
  • You should have a stone wall at the attacked position

Day 26-34

  • Your gold income is 800-1500 
  • Continue expanding 
  • Continue upgrading 
  • Continue getting more gold 
  • Continue building more troops 
  • Start looking out for a new space for a second city 
  • Only start building the second city if the space is 100% secured and you can take the ressource drain. It will massivly slow your progress but your gold income will be increasing massivly too. 
  • Think about having 2 ballistas at every wall (still 1 ballista and stone wall should keep your safe at this point) 
  • Dont have blind spots in your wall a ballista cant reach. Harpies can jump your wall and completly wipe you, before you even know what happened. 
  • You ask when to stop building troops? Do you have more than 1000 gold? Build more troops. The gold doesnt help you laying around!

Day 34

  • Get ready for wave 4 
  • You shouldnt have problems with this wave 
  • Still think about building a double stone wall

Day 34-41

  • Your gold income is 1200-2000 
  • Continue doing all that stuff 
  • Build a foundry 
  • Start researching oil plattform when you have enough gold 
  • Get oil 
  • Research engineering 
  • Research thanatos or titan 
  • Continue looking for more space to expand 
  • Continue building more residential 
  • Start looking out narrow entrances between mountains, water and wood, where you hold off the final wave

Day 41

  • Get ready for wave 5 
  • Have 2 ballistas, double stone wall and your troops ready

Day 41-47

  • Your gold income is 1500-2500 
  • Start building thanatos and/or titans 
  • Get more oil 
  • If you did well at this point you should have half the map 
  • Stop expanding if thats the case 
  • Concentrate on upgrading all your residential in your hopefully 2 villages 
  • Expand when you have additional ressources, while upgrading your houses 
  • Expand only to get more energy and food for your economy 
  • Continue killing everything on the map 
  • Destroy all remaining villages of doom and gather their ressources

Day 47

  • Get ready for wave 6 
  • Kill wave 6 
  • You see how cool thanatos and titans are? Get more of them!

Day 47-54

  • Your gold income is 2000-3000 
  • Continue clearing the map 
  • Continue upgrading your gold income 
  • Continue doing small expansions where
  • And whenever you can 
  • Continue building troops 
  • Build more ballistas at your walls…just…have a lot of them ready

Day 54

  • Get ready for wave 7 
  • Kill wave 7

Day 54-60

  • Your gold income is 3000+ 
  • Continue everything above

Day 60

  • Get ready for wave 8 
  • Kill wave 8

Day 60-66

  • Continue upgrading and stuffing out space you have left 
  • Start building a double double stone wall at all your defenses 
  • Start upgrading your first line of ballistas everywhere

Day 66

  • Get ready for wave 9 
  • Kill wave 9

Day 66-72

  • Stop upgrading residential 
  • Concentrate completly on upgrading all your ballistas 
  • Use all additional ressources to build more troops 
  • Split up your mechs and snipers wisely between your defenses 
  • Have your archers in the middle of the map as a mobile defense force 
  • Use earlier waves as a reference how the final wave will hit your defenses 
  • Your gold income should drop under half, thats completly normal

Day 72

  • Prepare for wave 10 
  • Dont freak out 
  • Spot weak spots and send the archers and remaining idle troops 
  • As soon as a spot looks clear enough, send all troops to the next spots 
  • If they look like they will break through at one spot (and you dont have units in range), just build random walls everywhere around it. It doesnt have to look pretty or effective, it just has to buy your time. Send troops to help contain it. 
  • If a breach happens, let your troops fall back and wall them off, so they can defend again 
  • Always have a wall between you and the wave 
  • Sell all your remaining oil and iron if you need more gold or stone

Day 75-80

  • Be happy its over 
  • Wait for the end 
  • Screenshot the result 
  • Prepare for the next map

How to React to a Zombie Village

Zombie villages or Village of Doom are fallen colonies. They can spawn zombies and will increase the final wave, if you dont destroy them in time.

  • Noise will trigger a 1-5 runner horde (shooting zombies near to the village), smaller events will spawn some slow walkers (building too near to the VoD). Those events can stack up, until you get a big wave out of the VoD. Attacking the building directly will trigger a runner horde per building around it (+ special infected sometimes).
  • Buildings of a VoD have a finite amount of zombies, you can simply wait and defend.
  • Destroyed VoD buildings drop 4 random ressources. 1k gold or 20 of each ressource.

How to react:

  • If you spot a village early, dont get nearer than your line of sight
  • Dont attack zombies near a VoD
  • Wall off the spot
  • Expand into other directions until you get ballista tech
  • Build 2 ballistas behind a double wood wall (or single layer stone wall)
  • Carefully trigger zombie hordes with your rangers and guide them to the ballistas
  • Make your stand until no more zombies come from the buildings
  • Destroy and loot the buildings


  • Dont waste time on VoDs too early. It can seriously delay your playstyle, since your are concentrating time and ressources on the VoD.
  • Dont be too aggressive. If you fail a raid on a VoD, you have an angry zombie horde on your hands.
  • If you trigger a VoD too early, try leading them away with one ranger. Dont run back directly to your colony, they will follow you!
  • Dont try to expand THROUGH a VoD. Even if you are good at destroying them, you will lose too much time. Expand into a direction without the VoD.

They Are Billions - How to Win in 80 Days
They Are Billions - How to Win in 80 Days

How to Survive the Final Wave!

  • Build enough ballistas. In the late game they are cheap since they only cost a few workers, 3 energy, wood and gold. You cant have enough ballistas. (just build them with purpose, wherever the strongest attack will come through
  • Build double double walls. Your main priority is to keep the hordes away from your first line of towers, as long as your can. A tower can shoot over 5 rows of walls. You cant build more than 2 rows of walls next to each other, so you build 2 double lines of walls. That should keep a final wave busy for some time.
  • Think about fallback lines. A fallen defense line isnt a lost game. Keep all places in mind where your troops can fall back to, and where you can put down another wall to stop the breach.
  • Split your troops equally between defense lines. have at least 1 thanatos at each defense line.
  • Every second watch your defenses. If one spot seems to be holding, pull off all troops from there and send them to more difficult positions. Never let your soldiers idle in the final wave. Put them, where they are needed most.
  • Make difficult desicions. Sometimes you have to sacrifice a part of your colony, so your troops can fall back and rally at a more narrow position. Sometimes half your colony is connected with the other half through only 1 spot. If you are overwelmed, fall back to that spot.
  • Give your defenses priorities. Put rangers and soldiers on “nearest target” and all towers, snipers and mechanical units on highest target. That way the AoE damage units focus the middle of zombie hordes and make use of their AoE and snipers and towers focus the big zombies (harpies, spitters and fatties)
  • Make a final stand at your headquarter. Remember: All zombies have their waypoint at your headquarter. Sometimes half your colony is still standing when you lose. Keep in mind that your headquarter is the only thing, that is really important to defend.

Additional Infos

1. What is the radius of the market and bank and how should I build my town?

They Are Billions - How to Win in 80 Days
They Are Billions - How to Win in 80 Days

Dont build houses outside that radius, it isnt worth it.

2. How should I react to an early village of doom, right next to my base?

They Are Billions - How to Win in 80 Days
They Are Billions - How to Win in 80 Days

3. What do you mean by double double wall? How does a proper defense looks like?

They Are Billions - How to Win in 80 Days

The point is to keep the enemy away from your towers as long as you can. Spitters can fire over a double wall. Towers can fire over 2 double walls. So double double wall it is.

4. Place down watchtowers. They are cheap and have near to none upkeep. You can see the whole wave and can deside earlier if that section needs help.

5. Place down quarries everywhere. Its cheaper than buying stone/iron. Even if its a 2 spot or on some crappy maps a 1 spot.

6. Place down warehouses next to your farms gives you a insane economy boost.

7. What is a killbox and how does it work?

They Are Billions - How to Win in 80 Days

If you build 2 rows of towers, the second row cant shoot until it is too late for the first row. This way you get way more towers into one spot.

8. Dont use advanced buildings. They are extremly expensive and inefficient.

9. Dont use executors before the final wave. They have a lot of upkeep and you could have used those ressources to expand. If you need executors before the final wave, you are dead either way.

10. What do you mean by narrow entrances to wall off?

They Are Billions - How to Win in 80 Days

11. Even if this place doesnt look important, it will get hit by half the south and half the east, because its the only way through.

They Are Billions - How to Win in 80 Days

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