They Are Billions is an ultra-hard RTS versus an AI opponent with a swarm of zombies that fills the map. It’s also kind of a city management game with a definite end point.

A good example of this is the resources. There’s an interesting mix of the static resources you’d usually see in something like Sim City or Caesar, and the stockpiling resources you’d see in Age of Empires or Starcraft.

Food, energy and workers are resources that stay static until you build again. You’ll always have the same amount of energy until you make another mill, or power plant, and you won’t run out of energy until you build something that saps it.

Wood, Stone, Iron, and Oil operate more traditionally — your buildings keep generating them, and they’ll stockpile forever. That stockpile has a maximum number (depending on how many warehouses you have), and anything above that is either wasted or automatically sold at the market.

A strong start is super important

Just like any RTS, an efficient start is paramount. Your build order will vary slightly, but there are some things you’ll want to do no matter what. For example: Right at the start, there’s a small window to build three tents before the next round of income arrives. If you’re too slow, you miss out on the gold those tents would provide.

It may seem small, but that little bit of gold has a cascading effect throughout the game, with bigger and bigger ramifications over the next four hours. It’s why build orders are so exact in games like Starcraft and Age of Empires, and this is no different.

So what’s generally a good guide?

On the first map, you’ll want to get these things done, mostly in this order:

Build housing and food, expand towards resources as necessary Build Soldier Center, make rangers and start clearing space Wood Workshop Farms, Cottages, Great Ballista, Market, Sniper Have a ballista on all choke points while rangers clear space Stone Workshop Stone Walls, Bank, Foundry

From there people start to vary in their playstyles, but you should aim to get up a Foundry, an Engineering Center, and pump out endgame units.

You can’t delete workshops to free up space. Doing so makes the techs you bought there unavailable. Expanding into large areas with good chokepoints is a must.

It’s unfortunate that you’ll have to spend several hours before you get late game experience. Suffice to say you’ll need more than one town’s worth of gold for the upkeep costs of units like Titans, towers, and armies of snipers.

Fight or Kite

In the early game, it’s possible to use the ranger’s speed to kite around a large group of zombies while a tower or other rangers fire freely.

You’ll find this tougher as the swarms become bigger though, and as more special zombies are mixed in.

Once the waves get too large, you can use a ranger to attract a blob of zombies away from the main horde. Perhaps you’ll bring them to another chokepoint, or perhaps you’ll just kite them around for a while to take some heat off your main section.

Plan for the late game

Take lots of space early, make sure it’s protected, and then build inside your walls. Save those grassy areas for farms later.

When building large housing districts, make sure to leave two holes in the middle for a Bank and a Market. These will raise income and reduce food usage, respectively.

Both the Bank and Market are 3×3 tiles, and can’t be placed next to another building. Here’s an example of an optimal layout, with the houses producting +30% gold and -30% food usage.

You may want to start building power plants later on (though some prefer advanced mills), and these consume 5 stone and wood every so often. Plan for this ahead of time by building more quarries and lumber mills than you need.

The rarest resource is stone. Later on you’ll want to build lots of stone walls, upgrade every cottage to a stone house and power plants will suck stone.

Plan for this by building several quarries and upgrading to advanced quarries.

Military Micro

Left to their own devices, units will wait until they see an enemy, then prepare to fire, and then fire. Setting them to Hold (H) causes them to prepare in advance.

They’ll effectively shoulder their weapon and aim before the unit comes along. A big deal when it comes to the long aiming time of snipers.

It’s also a great idea to tell your snipers, ballistas, executors and Thanatos to focus on high priority infected. The latter three are area of effect, so they’ll actually kill more infected by targeting VIP zombies in the middle of large groups.

I’ve even seen some Youtubers pausing often enough to carefully guide their Thanatos shots into the middle of standard zombie crowds for maximum effect, but that’s a level of pause micro I’m not willing to engage in.

Everyone beats the waves in their own way, but you’ll need to remember that the venom-spitting zombies are ranged, and can take out shock towers and other defensive buildings from afar. Especially so if your ballistas are focusing on other special zombies.

A tower full of snipers set to target high priority zombies can work well. Be sure to put it close to the front of your tower formation, so they outrange the spitters.

Time To Kill (TTK)

On the subject of unit strategies, here’s a table put together by Reddit user Tumulusx. This shows how many seconds it takes for each unit to kill each type of infected.

It doesn’t take into account factors like range, noise, armour and speed. But sometimes noise can be a good thing, as it makes luring and clearing large areas of zombies quick. It’s clear to see just how much an advantage you have when you can start spending iron on soldiers and snipers.

Young, Aged,

Decrepit Fresh, Colonist Executive Harpy, Venom Chubby Ranger 4 5 9 14 75 V Ranger 1.5 2.5 4 5.5 30 Soldier 1.5 2 3 4.5 23.5 V Soldier 0.8 0.8 1.6 2.4 11.2 Sniper 2.2 2.2 2.2 4.4 15.6 V Sniper 1.1 1.1 1.1 2.2 6.6 Titan 0.4 0.6 1 1.4 6.8

The “V” before some entries marks that as a veteran unit, obtained after killing many infected.

The Lucifer and Thanatos are omitted because they’re moreso instant kills within an area of effect. But it’s worth bearing in mind Thanatos has a large reload time on his rocket launcher.

Reject the Early Thanatos

Some mayors will offer you units like Thanatos very early on. It’s tempting, but units like this will agro a whole section of the map when a swarm comes. It’s pretty much impossible to deal with in the early game.

I found this out the hard way. Learn from my mistakes.

Clear the map, grab space

This is key to making sure your units are veterans when the later waves come.

Taking out the villages of doom can also give you some nice resource boosts. If you’re ever in a tight spot, you can run over those crates and just keep building.

Once you have a large group of snipers, there’s not much they can’t handle. They’ll help a lot in the tougher edges of the map where a lot of special zombies reside.

The Scratching Post

Zombies are dumb and will attack whatever is in front of them. Putting a solitary wood wall tile at the edge of your base will attract the lone zombies wandering in to test your defences. It’ll give you enough time for your rangers to run over and save the day.

It also costs next to nothing and is infinitely better than just having houses on the very edge of your base.

Pausing and Destroying

You might initially feel queasy about pausing the game, or destroying buildings. That’ll pass.

Every time you hear an attack alert, your reaction should be to pause the game, check it out, and then continue. If you see some red dots rushing at you on the minimap, pause. If you have a lot of building decisions to make at once, pause.

Same thing goes with destroying buildings. If you’ve expanded beyond your initial perimeter, you might have ballistas sucking up gold upkeep for no reason.

You can also pause buildings, such as quarries producing stone when you’re at maximum and don’t have a market. If you get into a tight spot and need a little bit of emergency power to get your economy running again, this can be a good option.

The Last Wave Is Brutal

It’s much harder than the periodic waves. It comes from all sides and they are… Well. Not quite billions, but it’ll feel like it.

At this point in the game, success will depend on your chokepoints, and whether or not you build an economy strong enough to support an army of Engineers Center units, snipers, and lots of towers and walls.

Hopefully that helps you take on the first map and beyond. Don’t be discouraged if you don’t win for a while. The long nature of the game means you have to invest three hours just to get some late game experience. It’ll be worth it to get that elusive win.