The Maps in They Are Billions are quite small and full of zombies and villages of doom. Huge zombie swarms spawn at the edges from time to time and try to run your Command Center down. Currently there are 6 types of procedurally generated maps in the game, which are ordered in difficulty and need to be unlocked.
There are six unique map themes, each having their own weighted odds on world layout and resource values.
| Map ⇅ | Hunting Food Modifiers ⇅ | Game Modifiers ⇅ | MaximumScore Factor ⇅ | OST ⇅ | Column 6 ⇅ | Column 7 ⇅ |
|---|---|---|---|---|---|---|
| The Deep Forest | 15% | 30% | 60% | 0-1 Doom Villages? Treasure PilesNo special infected | 410% | Crimson Leaves |
| The Dark Moorland | 15% | 30% | 60% | 1-2 Doom Villages5-6 Treasure Piles | 520% | The Dark Moorland |
| The Peaceful Lowlands | 10% | 30% | 50% | 4-5 Doom Villages4-5 Treasure Piles | 590% | Danger From Within |
| The Frozen Highlands | 0% | 40% | 60% | 1-2 Doom Villages4-5 Treasure Piles130% Building Energy50% Zombie Awareness80% Run Speed | 700% | Sharp Frozen Teeth |
| The Desolated Wasteland | 0% | 30% | 60% | 3 Doom Villages7-10 Treasure Piles130% Zombie Awareness110% View Range for units and infected | 800% | Derelict Sand Castles |
| Caustic Lands | 15% | 30% | 60% | 1 Giant Doom Village5-6 Treasure Piles | 900% | Caustic Steam |
In the depth of this forest there is peace and security. It seems that the infected shun these types of places. However, be careful, a colony full of humans doesn't go unnoticed to the sensitive senses of infected even if they are days away.
The basic map, which is unlocked right from the beginning. Has lots of pockets and choke points to expand and defend, and has no special infected on the map. Only the final waves spawns all special infected that are in the game, otherwise waves only spawn normal, fast and chubby infected.
In the Dark Moorland, the terrain is very intricate as it forms gorges and small plains with rivers and pools. These terrain formations can be very useful to protect against the infected, but will make expansion of the colony much harder to achieve.
Requirements: Finish the Deep Forest with a score factor of at least 20% to unlock.
Not a lot of free space, many small water patches. Construction is limited by terrain, so housing blocks will usually be smaller than on open maps. Contrary to description, expansion is easier, because units usually need to push in only one direction, and usually there are multiple pockets. The forest patches and small lakes reduces the number of walls needed to sufficiently defend the colony, making construction of fortifications much cheaper. This is the first survival map that starts generating special and giant infected.
Many tiles in this mode tend to blend together. It can be difficult to visually distinguish between dirt, water and Executives, especially under fog of war or in Flat Mode.
Surely, you will think at first sight that the Peaceful Lowlands is a nice place to settle a colony. But that is the same thought that many people of the past had a long time ago until the infection spread to their villages. Now there are many Doom Villages threatening these peaceful lands. Be careful with them.
Requirements: Finish the Dark Moorlands with a score factor of at least 40% to unlock.
Has much more open space than the Dark Moorlands and Forest. This makes building productive city blocks easier, but requires higher investment into fortifications. Multiple Villages of Doom guarantee that colony will be assaulted by regular waves of runners from multiple directions. Despite lack of chokepoints, large lakes can block off 20-40% of the map.
Huge areas of map near center can be cleared by a small group of rangers. Don't get greedy and make sure colony is enclosed by day 20. After day 20 expansion into big open areas becomes complicated by runner mini-waves; use Wasps to protect recently cleared areas.
The frozen highlands, the big mountain ranges reach the sky. Between the mountains, there are vast frozen valleys and lakes. The cold can be your worst enemy. Buildings require more energy to keep them warm and units walk slower. The good news is that the infected activity is much lower because of cold.
Requirements: Finish the Peaceful Lowlands with a score factor of at least 60% to unlock.
This map is built like the Dark Moorland in winter. The infected are less aggressive on this map, meaning that noise and death of other zombies will attract less attention.
The challenge lies in a higher energy usage and all units are slowed due to coldness.
Ranger move speed is 3.2 versus 4.0 in Dark Moorland, thus one may assume 20% reduction for all units.
Without a doubt, this is a terrible place to found a colony. Although these arid lands have much more mineral deposits and oil than any other terrain, the land is very open therefore the visibility distance is very high. Lots of small colony groups have died in this dry land. What's worse, the infected seem much more active under this warm climate.
Requirements: Finish the Frozen Highlands with a score factor of at least 80% to unlock.
This map is a challenge map tuned to be about as hard as a map can be and still maybe be beatable. The Desolated Wasteland is a fairly open map with a large number of Villages of Doom, similar in some ways to the Peaceful Lowlands. However, unlike the Peaceful Lowlands, unbuildable terrain tends to be produced in numerous small clumps, and mesas are much more common than forests or water tiles. The narrow passages between these clumps mean that they provide little protection from wandering infected. Water terrain on the Desolated Wasteland is generated in such small patches that they often appear as simply cracks in the ground with no visible water tiles. Forest patches tend to be small, with forest tiles being represented as either Saguaro Cactus or Ponderosa Pine. Mesas are common, but tend to be smaller than those on the Dark Moorland. It is not unusual for there to be hard to see paths through what looks like solid terrain. Stone, iron and oil sources are plentiful, and often in large patches, however this further reduces the useful building space, making finding a good spot to put housing difficult despite the openness of the terrain. Like the Frozen Highlands, green patches suitable for farmland are fairly rare, forcing you to expand aggressively toward fertile areas if you are to keep your population growing.
The challenge lies in the combination of a low number of grass tiles, and higher than usual zombie aggression resulting in both food shortages and large groups of zombies coming to investigate even the smallest disturbance. It requires great skill and maybe a little luck to beat this map at the higher difficulty levels. Expect to lose a lot on this map, as it is about three times harder than the first three maps. Challenging on map 4 is considered by many to be much more difficult than Brutal on any of the earlier maps.
Perhaps, the most terrible place to build a colony. The lands of this place are ash from volcanic eruptions of many years ago, and its caustic waters shine with a brighter green color that seems to attract the most powerful infected. At least, this land is rich in minerals and metals. Be careful with Doom Colony!
Requirements: Finish the Desolated Desert with a score factor of at least 100% to unlock.
This map has the highest count of special infected and one giant doom village. Terrain generation is capable of generating a lot of closed areas. Iron and gold may spawn near center of the map. Walkers and mutants start spawning closer to Command Center than on most maps as well.
Despite higher score modifier, Caustic Lands is arguably easier than desolated wasteland because it always has only one village, plenty of farming land and no dreaded zombie awareness buff. The expansion is constrained by higher number of Infected early, but that's eventually compensated by resources acquired from Colony of Doom. It is also more likely to spawn with many choke points and pockets.
Usual strategy involves pushing with rangers from the start and trying to identify the location of the village. It can be identified both visually as well as by line of walkers after day four. By day 20 there should be a line of 3-5 Ballistas protected by walls between command center and colony, because from now on the village will send continuous stream of runners.
Scouting with Lookout Tower and infected Radars can be very useful, because they can identify isolated areas of the map. Eventually The Silent Beholder can help identify the best choke points for final wave; it isn't rare to have maps with as little as 3 potential entrances into colony. Don't expect units to scout the entire map, with higher infected density and multiple mutants that is fairly challenging.
Pulling runners with rangers into ballista range or stakes traps can help quickly clear parts of map near command center.
Good army to clear the village of doom quickly consists of 5-8 lucifers/3-4 titans and 30-60 snipers, although pushing it just with snipers and rangers for resources is also acceptable.
The colony of doom can drop hundreds of thousands of gold and thousands of every other resource. Before pushing into village, make sure to have ways to store and spend the collected materials quickly. All resources collected above cap will be wasted. 5+ Warehouses is a must. Have 4-6 barracks producing units continuously, bind one command group to cottages to upgrade them, be ready to invest into wonders.
Clearing the map entirely before the final wave may not be always possible, but at least make sure to get rid of most Giants.