Raids on your base

Your base is attacked only at night and only while you are at home. Nothing attacks an empty base, but a horde you dodged by being away is not forgotten: it makes the next nights at home more likely to bring one, and a bigger one.

Zombie hordes

• A horde comes at most every 3 nights. Each night the chance runs from 10% up to 75%.
• The chance grows with the noise you make at home (gunshots, explosions, the helicopter, breaking things), the value of your base (what its pieces are made of), polluted air at home, and the nights since the last horde. Noise fades by half every 24 game hours.
• It arrives between 21:00 and 02:00, with a warning 1 game hour before (about 40 real seconds).
• A horde has 3–12 zombies, more as the pressure grows. Your first 2 hordes are smaller (2–6).
• Zombies come in from the trail and look for the weakest way in: they break doors and walls where it costs them least. At dawn the survivors walk off.
• When the air at home is above 30% pollution, toxic mutants join the horde (up to 50% of it). They are slower but hit 1.75× as hard, and every hit makes you more toxic.

Raiders

• Raider squads come on their own nights (a horde and raiders can come on the same night, and then they fight each other too). The chance runs from 5% to 35%, at most every 4 nights.
• It grows mostly with how much the Raiders hate you (see factions), and with your base’s value and the nights since they last came.
• A squad has 3–6 raiders: Rifleman, Close quarters and Heavy. They fight from cover, shoot through windows and open doors, and break through pieces in their way.
• Once half the squad is dead the rest walk off. If you leave or die while raiders are still at home, they loot your crates, lockers and stash (the most valuable things first, up to 150 value per living raider). The turret’s ammo box is safe.

Defences

Defence	What it does
Spike barricade	Hurts a zombie by 6 each time it strikes, and anything pushing against it by 4 a second.
Barbed wire	Slows everyone crossing it to half speed and hurts zombies by 2 a second, and you by 0.5 a second. It wears down as zombies cross it.
Sandbags	Low cover.
Turret	Needs power. Shoots the nearest zombie within 10 tiles that it can see, one round every 0.4 s, at 1.5× the gun’s damage. Load loose 5.56 Round or 9mm Round into its ammo box.

Grenades that go off at home damage nearby pieces, and bullets that stop on a piece damage it a little. Repair damaged pieces with the Hammer. Home portals take damage too but never break: at 1 health a portal is knocked out and takes no one through until you repair it.