A run is four layers stacked in a fixed order: hull blocks create space, modules occupy that space, people and power make the modules run, and defence keeps the first three alive. Almost every build mistake is a mistake about that order — expanding before production, or adding guns before deciding where the aliens will walk.
Everything below is the reference for those four layers: what each part does, what it costs, and which pieces compete for the same input. Values that change with a patch are written as mechanics rather than fixed numbers, because the ship you build is the only thing the game keeps constant.
The four layers, in order
Hull blocks are the floor plan. Modules are the rooms. Humans and power are the staff and the electricity. Defence is what stops the other three from being demolished while you are not looking.
Each layer constrains the next one. A module needs a slot, a slot needs a block, a running module needs power and a worker, and a worker needs somewhere to live that is not currently on fire.
That is why the ship's weight matters as much as its output. Every module you add makes the ship heavier, so the balance you are actually managing is energy consumption, fuel production, available workforce, ship weight and defensive needs at the same time.
Modules and what they are for
Modules are built to produce resources, repair damage, boost efficiency and reinforce defences. Those four jobs compete for the same slots, the same power and the same people, which is the entire tension of the build phase.
Some modules buff the structures next to them rather than producing anything themselves. Despot's Chamber is the known example: it improves the efficiency of neighbouring modules, so where you place it changes what the modules around it are worth.
Modules do not arrive as a shopping list. You get module kits, and Despot's Chamber produces them from your workforce, which means production capacity and building capacity are the same resource seen from two angles.
| Module job | What it does | What it costs you |
|---|---|---|
| Production | Converts inputs into resources, humans included | A slot, power and a worker |
| Repair | Restores damage to the ship | Power and a worker |
| Efficiency | Buffs adjacent modules instead of producing | A slot that produces nothing directly |
| Defence | Reinforces what the aliens are trying to break | Power, and a slot on the route |
The resource chain
Build cost moves through two stages. Early construction is paid for in Energy, and later construction shifts to Plasteel, so a run that never solves its energy income stalls before it ever needs the second material.
Humans sit underneath all of it. They are the labour that runs modules, the fighters that hold the airlock, and the input that the bioreactor converts into fuel when the population is larger than the ship can use.
Fuel is what keeps the ship moving, and moving is the one thing the ship is not allowed to stop doing. Converters handle the repetitive part of that chain and have an Auto setting, which exists mainly for the bioreactor so you are not clicking it every few seconds.
| Resource | Role | Where it comes from |
|---|---|---|
| Energy | Early build cost, runs modules | Production modules |
| Plasteel | Later build cost | Production modules, later in the run |
| Humans | Workers, fighters, fuel | Population, reassigned between the three |
| Module kits | What you actually build with | Despot's Chamber, from workforce |
| Fuel | Keeps the ship moving | The bioreactor chain |
Hull blocks and module slots
Hull Construction deals fifteen block shapes per run, at random and without repeats until the pool is exhausted. None of them rotate, and none of them can be placed over the airlock or the engines.
A placed block cannot be destroyed. That single rule turns layout into a commitment: you are not editing a floor plan later, you are deciding now which route the aliens will take for the rest of the run.
The launch build also lets you build on any empty module slot. In the demo a slot only opened once a completed module sat next to it, so layouts that were impossible in June are legal now.
Turrets and how a breach actually plays out
Drop pods land on different parts of the upper and lower hull, and whatever is inside walks toward the airlock. The route they take is made of your corridors, which is why turret placement is a layout question before it is a damage question.
Turret slots accept a weapon you can upgrade, or replace later with a higher tier one. Ranged weapons punch through a line of attackers, while close-range weapons hit harder and can ricochet into a second target standing nearby.
Weapons also apply effects: slowing what they hit, making it take more damage, or poisoning it over time. On a long corridor those effects do more work than raw damage, because every second an alien spends walking is a second your guns are firing.
Ships, modes and difficulty
There are three ships, six modes and four difficulties, and you start with one ship and Classic Mode. The rest unlock through progression rather than through a menu.
The three hulls are not skins. Each has its own layout, its own systems and its own loss thresholds, so a build that works on one is not automatically a build that works on the next.
Three modes are named: Classic is the twenty-wave run, Trade drops combat and keeps the economy, and Endless continues past the twenty-wave target with its own scaling. Endless is a separate mode at release rather than something Classic rolls into.
| Axis | Count | What changes |
|---|---|---|
| Ships | 3 | Layout, systems, loss thresholds |
| Modes | 6 | Whether combat, economy or scaling drives the run |
| Difficulties | 4 | Pressure, not rules |
| Classic length | 20 waves | One wave per day of the decode clock |
Reading a stalled ship
When a run stops progressing, the cause is usually in the layer below the one you are looking at. A module that will not run is a power problem, a power problem is a production problem, and a production problem is usually a staffing problem.
Check the chain in order: is the module staffed, is it powered, does it have inputs, and is there anywhere for the output to go. Most "broken" modules are simply the last link in a chain whose first link is missing a worker.
Power is the hard ceiling
Slots are limited by hull blocks and modules are limited by kits, but both are useless without generation. A build that adds capacity without adding power stalls in place while looking finished.
If the ship is running fine and the game itself is slowing down, that is a different problem with a different cause — see the wave 40 page. If you want the order to build in rather than the parts list, start with the first twenty waves.