This is a guide to Flocking Hell, meant to explain a bunch of game mechanics that the game shows implicitly but not necessarily explicitly or in numbers.

The first three sections (Island, Demon Invasion, and Production) cover basic game mechanics. The last few sections cover strategy.

The game has received a bunch of updates since its release in 2025-03. This guide is up-to-date as of Patch #6 from 2025-09-11.

(Terminology: "adjacent" here means "any of the 4 orthogonally adjacent tiles" and "surrounding" means "any of the 8 orthogonally or diagonally adjacent tiles".)

• Each island consists of 10x10=100 tiles.
  
• Each island contains 12 cities, at a distance of at least a knight's move from one another.
  
• Each city is surrounded by pasture tiles which indicate how many cities are on the surrounding tiles. (Small Pasture, worth 1 sheep: 1 city; Large Pasture, worth 2 sheep: 2 cities). Any empty tiles that do not have a city on a surrounding tile are Grassland, worth 2 sheep. This information can be used to locate cities, similar to Minesweeper.
  
• Each island contains 1 Cottage (9 sheep) which is surrounded by 8 Large Farms (5 sheep). On a ring surrounding those Large Farms, any Grassland tiles are replaced by Small Farms (3 sheep).
  
• Each island contains 7-9 mountain tiles which form either a jagged mountain shape, or a horizontal or vertical mountain range with exactly one passable canyon in-between.
  
  • 3 of the mountain tiles are Mines, which cannot be adjacent to one another.
    
  • Mountain tiles are automatically revealed when an adjacent tile is revealed.
    
  • You cannot reveal tiles across a mountain tile.
• Every island contains special tiles: 4 beacons (always adjacent to a city), 3 observatories, or 2 teleportation pools.
  
  • When the 4 tiles surrounding a beacon are revealed, it lights up, marking another beacon (or the Hell Gate if all beacons have been marked) and granting the adjacent city +1 attack.
    
  • When an observatory is connected via a road to a city, all 8 tiles surrounding the observatory are revealed.
    
  • When a teleportation pool is connected to a city, the other teleportation pool is revealed, and both pools count as connected for the road network.
• One tile on the edge of the map is a Hell Gate. It is immediately revealed if an adjacent tile is revealed. It is never directly adjacent to a city. If you manage to reveal it before the demon invasion on turn 80, your Crystal Blast gets +40 bonus damage.

After 80 turns, the demons invade. Here's what happens, in order:

First, the invading demon horde is struck by your Crystal Blast, which kills a number of demons equal to your accumulated crystals. If you've revealed the Hell Gate, your Crystal Blast gains +40 strength.

Then, the surviving demons attack your cities. Until the horde is defeated or all your cities are razed, it loops through these steps:

• Pick the next attack target: that's always the city that's closest to the Hell Gate, or to the city which the demon horde has just razed. As a tiebreaker, if two cities are equally close, then the horde attacks the city with less population. (You can see the attack order of the demon horde by hovering over the Hell Gate.)
  
• Attack the city. The horde and its attack value face off against the city's population (plus reinforcements equal to 5 times the number of other connected unrazed cities) and its attack value. (Also, the first attacked city gets a negligible "Leftover" size bonus equal to your unspent sheep.)
  
• Determine casualties. At equal attack values, a city of population N kills around N demons. If attack values are unequal, then the number of killed demons is multiplied by attack_city divided by attack_horde. So if the horde has twice the attack value of the city, it takes half the casualties, and vice versa.
  
• If the horde survives, it razes the city and gains +0.5 attack.

Because the horde gains attack after razing a city, it is much better to buff a high-attack city that gets attacked early on by the horde, rather than having a bunch of weak cities at the front of the attack order which inflict hardly any casualties but severely increase the horde's strength.

Also, a strategy based on connecting cities gets a significant city size bonus due to the reinforcements mechanic, which makes it more likely that the cities that are attacked early on have the highest number of defenders.

(Feel free to skip to the bolded parts if you don't like math.)

Cities begin at 3 attack, gain +1 attack once they've been fortified, and can gain additional attack from beacons, cards, or island effects. For cities, the math is simple: increasing their attack from A to A+1 increases demon casualties by (A+1)/A. For example, increasing city attack from 3 to 4 to 5 to 6 is worth 33%, 25%, and 20% casualties respectively. In other words, if you have a city with population 100 and attack 3, then giving it +1 attack is worth the same as giving it +33 population.

The demon horde begins at 3 attack (3.5 on Competitive² difficulty) and gains +0.5 attack per razed city, up to +5.5 attack for razing 11 cities and fighting the 12th, at which point it has 8.5 (9) attack. In contrast to cities, the increased attack values for demon casualties have diminishing returns: increasing demon attack from A to A+0.5 reduces demon casualties by 1-A/(A+0.5). For attack values 3, 3.5, 4, 4.5, 5, that's worth 14%, 12.5%, 11%, 10%, and 9% respectively, down to 5.6% for the jump from 8 to 8.5. The numbers are clearer to understand if we just talk about multiplying demon attack values: jumping from 3 to 4.5 demon attack, a 50% increase, reduces casualties by 1-1/1.5=33%. Jumping from 3 to 6, a 100% increase, reduces casualties by 1-1/2=50%.

Finally, how does gaining crystals compare with increasing population size?

• The first city to be attacked has attack 4 (from fortification) while facing a demon horde with attack 3. Giving this city +pop causes 4/3*pop demon casualties, so every point of population gained is worth the same as gaining 4/3=1.33 that amount in crystals. (On Competitive² difficulty, the demon horde has 3.5 attack, so there +pop is only worth 4/3.5=1.14 that amount in crystals.)
  
• The 12th city to be attacked has attack 4 while facing a demon horde with attack 8.5, so there a population increase is only worth 4/8.5=0.47 that amount in crystals.

You have 80 turns until the demon invasion occurs. On every turn divisible by 5, production occurs, i.e. on the turns when the turn counter says 75, 70, ..., 0. If there are ≤5 turns remaining, you can skip the remaining turns to get some bonus crystals, but you still get the final production phase.

This means that there are a total of 80/5=16 production phases per island.

During a production phase, each mine produces crystals equal to the number of assigned sheep, i.e. 5 or 10 per mine.

Straightforward implication: the earlier you assign sheep to a mine, the more crystals you will produce. If you can find a mine and assign 10 workers within the first five turns, you get 10*16=160 crystals, or 16 crystals per sheep. If you only find the mine around turn 40, you miss out on 8 production cycles and only get 10*8=80 crystals, or 8 crystals per sheep. And if you find a mine very late, it's probably not worth assigning any sheep to it.

During a production phase, each revealed city grows by 1 plus the number of cities in their connected road network. A city without roads therefore grows by 1+1=2 per production cycle, whereas if all 12 cities are connected, each one grows by 1+12=13 per production cycle.

In contrast to mines, there is little value in connecting a few cities early. Roads are expensive, and each individual production cycle isn't worth much. The true power of connecting cities only becomes apparent if you manage to connect a lot of them, ideally all of them. Then this game mechanic snowballs.

Below I've made a table of who this looks like in practice. As you can see, connecting 2 cities with roads only yields 2*1=2 extra population per production cycle, which is negligible when compared to the steep cost of placing roads. Even connecting 5 cities only produces a total of 5*4=20 extra population per production cycle: 10 times as much as connecting two cities, but still negligible. But once you reach e.g. 10 connected cities, that's worth 10*9=90 extra population, so another 4.5 times as much as connecting 5 cities. And connecting 12 cities is even better: you get +42 extra population per production cycle, just for connecting two extra cities.

You have three limited resources, which you must manage wisely:

• Actions: you only have 80 turns, which is not enough to do everything. Revealing a tile, placing a road, or playing a card all cost one precious turn.
  
• Sheep: you only have a limited number of sheep to do your actions with. Placing a road, assigning sheep to a mine, and playing cards all cost precious sheep.
  
• Production Cycles: you only have 16 production cycles. If your strategy is based on assigning sheep to mines or on connecting cities, then there are significant benefits to doing this early on while there are still many production cycles left.

• These actions are always high-value: revealing the Cottage (worth 9 sheep) or the surrounding Large Farms or Small Farms. Revealing the Hell Gate. Playing the best card(s) in your deck.
  
• These actions are always low-value: revealing a Small Pasture tile (worth 1 sheep) which doesn't help you identify the city location.
  
• For other actions, their value depends:
  
  • Revealing a city: this doesn't yield any sheep, but it makes the city grow by 2 per production cycle. Also, you need to reveal your first city before you can play any cards. That said, whether you'll benefit from revealing lots of cities depends on your cards and your Guides.
    
  • Revealing Large Pasture tiles or Grassland tiles (worth 2 sheep each) is usually decently valuable, but only once few turns are left and you've already done anything that's higher-value and anything that scales with production cycles.
    
  • Playing starter cards can range from "genuinely valuable" to "worthless except to get to your good cards". However, since many strategies spend a lot of actions on playing cards, it's important to find a strategy which makes good use of your starter cards.
    
  • Finding the Cottage is high-value, but spending tons of actions on doing so is not. Hence it's important to find it with the least number of actions. The Cottage is always surrounded by Large Farms, and the resulting 3x3 shape doesn't fit on a lot of places on the island. This can help you locate it. In addition, many cards and Guides help you find it, e.g. by marking a farm tile or the Cottage, or by revealing tiles elsewhere on the island from which you can manually reveal further tiles.
    
  • Building roads: connecting an Observatory to a city is usually worthwhile. Meanwhile, whether it's worth to connect cities depends entirely on your strategy.
    
  • Assigning sheep to a mine: at best you get 80 crystals per turn spent on assigning 5 sheep to a mine. This is usually worthwhile in terms of actions, but not necessarily in terms of sheep.

Many Guides and cards affect the value of your actions. For example, the Scout Guide reveals an adjacent tile when you reveal a city, which therefore increases the value of revealing cities.

• Assigning sheep to a mine: at best you get 80 crystals per 5 sheep spent on a mine. This is usually worthwhile unless you need all your sheep for playing cards or building roads. However, if you find the mines only after several production cycles have passed, this becomes much less valuable.
  
• Playing cards
  
  • The first card played on a city fortifies it, granting it +1 attack. This is most valuable for big cities that are early in the demon horde's attack order.
    
  • Your deck contains one-time cards, which are marked in the top-right corner. This includes one of your starter cards and all of your rare cards. Playing such cards exhausts them, removing them from your deck for this island. This makes your deck smaller and allows you to find your other starter cards and common cards more frequently.
    
  • Choosing which of the two cards to play: because the card you don't play is discarded and won't be redrawn until your deck is shuffled, you'll usually want to play your overall best card, but not always.
    
  • Often you'll need to play an irrelevant card so you can find your relevant cards. In these situations, playing the net cheapest card is best. In particular, cards which reveal tiles are essentially cheaper on net because you'll get back sheep from revealing those tiles.
    
  • For cheap cards, the cost of the turn spent playing the card can outweigh the cost in sheep.
• Building roads: As mentioned in the sections on Production and on Combat, connecting cities into a big network yields extra population and extra reinforcements. However, trying to connect all cities is a very big undertaking and leaves very little sheep and turns for anything else. This is only worth doing if your cards and Guides require or support this.

At the highest level of abstraction, there are only two options for how to defeat the demon horde:

A) Focus on collecting crystals to the point that your Crystal Blast almost or entirely annihilates the demons. This requires the use of cards, since each crystal mine can generate at most 160 crystals per island (so 3*160=480 for all three mines), and less in practice.
B) Strengthen your cities by fortifying them, connecting them, and/or buffing them with cards.

To which extent you should pick A or B depends on your starting deck and your guide options.

A campaign consists of 6 regular islands followed by one boss island. After completing any island, or after losing on an island while you have a spare life, you have the option to draft one of three cards. After completing islands 1, 3, and 5, you get a choice of one of three Guides.

Your initial deck consists of:

• 1 out of 2 possible one-time starter cards: either Map to the Cities (mark 2 cities) or Map to Riches (mark a farm and a mine).
  
• 2 out of 4 remaining starter cards
  
• 1 common card drafted out of 3 choices. Most common cards grant population or crystals, while a few either grant sheep or make other actions cheaper. None of the common cards are one-time cards.
  
• 1 rare one-time card drafted out of 3 choices. Most of these are straightforwardly one-time cards, while a few cards put extra cards into your deck.

Regarding the one-time starter cards:

• Map to Riches: mark a farm and a mine. This is a great starter card, since finding the Cottage is among the most valuable things to do in the game, and this card makes that very easy. Strong in general. Has some synergy with strategies that want to assign workers to mines.
  
• Map to the Cities: mark 2 cities. Since the marked cities are random, the impact of using this card varies, but overall I find it much less useful than Map to Riches. Helps with strategies that want to find and fortify or connect lots of cities. Lacking a way to find the Cottage makes it higher priority to obtain other ways of finding it: like Witching Hour, Move-In Day, or other cards that reveal tiles.

Regarding the other starter cards:

• Frenzied Fortification: costs 2, does nothing. Unimpactful. Slightly helpful for strategies that want to fortify lots of cities or play lots of cards.
  
• Observation Tower: costs 3 and reveals 2 adjacent tiles. Often only costs 1 on net after revealing pasture tiles, which makes it a more generally useful card than Frenzied Fortification. Saves on actions for revealing tiles, which means you get more turns for other tasks. Synergizes with Charms like Revealer Charm (from Call to Arms) and Lattice Charm (from Into the Matrix) that like revealing tiles.
  
• Pen Pals: reveal the nearest hidden city. Helps explore the map more quickly by revealing distant tiles. Revealing lots of cities is helpful for some strategies and detrimental for others, so try to use a strategy for which it's helpful. Synergizes with cards that care about the number of cities: namely Alchemy (gain 4 crystals for each fortified city) and the three Symbiosis cards (grant a bonus for each city that had a Symbiosis card played on it).
  
• Pioneers: reveal a random hidden pasture. Only costs 2 on net after revealing pasture tiles, which makes it a more generally useful card than Frenzied Fortification. Saves on actions for revealing tiles. Helps explore the map more quickly by revealing distant tiles.

Whether for the initial deck or later on, it is advisable to draft cards that complement your existing deck and your guides. So let's talk about archetypes.

The only archetypes that want to build roads are Go Wide (connect all cities); or Go Tall (if it has cards or Guides which want five connected cities). All archetypes can assign sheep to mines unless their best card provides a better effect than the up to 80 crystals gained from assigning 5 sheep to a mine. But the rest of your sheep is spent on cards, hence the need to draft a deck that can make good use of those cards.

• Go Tall: Grow one city as big as possible with cards that grant population or +attack to a specific city. This strategy wants to reveal relatively few cities, connect few or none of them, and to grow the city that's closest to the Hell Gate. A related version of this archetype wants to connect and fortify exactly five cities to make use of cards like Population Boom ("if you have at least 5 connected, fortified cities, this city gains +1 attack"). This archetype also likes having a card that helps you identify the Hell Gate, like Vanguard ("the revealed city closest to the Hell Gate gains 20 pop").
  
• Go Wide: Connect as many cities as possible, ideally 10+. This is the way the game is meant to be played, but on the highest difficulty levels this archetype feels rather weak. You're at the mercy of the map generation which sometimes makes a few cities almost inaccessible; placing roads is extremely expensive in terms of both sheep and turns; you're almost forced to reveal the cities before you place the roads in order not to accidentally place superfluous roads (thus wasting 5 sheep per road), etc. Synergizes with cards that reveal tiles, that mark or reveal cities, that help build roads, that accumulate extra sheep, or that require or benefit from connecting cities (e.g. Common Roots: all cities connected here grow). But you'll have few spare sheep to play those cards.
  
• Go Boom: Focus on gaining crystals from mines and cards. Leaving aside Shining Symbiosis as a separate archetype, that encompasses cards like Alchemy (gain 4 crystals for each fortified city), Compounding Wealth (gain 10 crystals, and automatically play this card if you produce 20+ crystals), Dual Fortune (gain 18 pop and 18 crystals), Into the Matrix (gain the Lattice Charm) plus cards that reveal tiles, Miner Expedition (assign more workers to mines, and at a discount), the rare card Ritual of Refraction, etc. You'll still need to reveal and fortify cities, however.
  
• Symbiosis: This is a narrow but super powerful archetype. If you start with Pen Pals (reveal the nearest hidden city) and can pick Expansive Symbiosis or Shining Symbiosis (gain 7 pop or 8 crystals times the number of cities you've played a Symbiosis card on) as your common card, that's enough to win. Your initial deck only contains three cards that are not exhausted after playing them, so if you play the Symbiosis card as often as possible (and use your other turns only to accumulate extra sheep or reveal remaining cities), you'll get more than enough crystals or population to beat any horde even on Competitive² difficulty. Do not add any common cards to your deck, though, except for the other Symbiosis cards.

If you're already deep in an archetype, go all in and draft cards and guides that support it.

Or if none of your card options support it, skip those cards; it's very easy to make your deck way worse by adding an unsynergistic card to it.

Conversely, for the draft at the very start, think about how your starter cards support your various card options, and pick options that push you into an archetype. Then after finishing the first island, you get your first Guide which further helps determine the direction of your current campaign.

Hopefully you found this guide useful! If you did, I'd appreciate a thumbs-up. And if you have any questions, feel free to ask.