The Attack
The Attack of the Hordes takes place every night at midnight (23:00 game time in the UK version), the zombies attack the town and attempt to kill citizens. Citizens who die outside during the night will be added to the horde. The citizens in town must build various defences to keep the shuffling, groaning masses at bay.
How many zombies get in is simple. If the town's defense is more than the amount of zombies attacking, then you will be safe and the citizens inside town will suffer no damage. If the town's defense is lower than the amount of zombies attacking, then some zombies will be able to enter town and kill or terrorise the citizens. Note that if the gates are left open, then the town defense does not matter and all the zombies will make it in.
The attack has a relatively predictable pattern. It will steadily increase for two to three days, then suddenly "spike" approximately every four days to hope-crushing heights. On this spike, the size of the attacking horde will be larger than average, and it may be difficult to gather the needed defense. The day after the spike, however, the attack will return to average or below average for a day, possibly even decreasing in number temporarily.
Any zombies who make it into the town are randomly divided between the members of the town. Resisting these zombies is the duty of the defense rating of your house; 1 point of home defense = 1 zombie turned away. If you are assaulted in the night, but survive, you will start the next day 
Terrorised.
However there is a small chance that you were attacked but did not get terrorized. In which case, the message from the Crow will be as followed:
"You were really sweating last night! You heard them groaning, banging around and yelling outside. Eventually your door gave way and you took refuge under your bed, clutching your remaining possessions, trying not to think about the situation. Then they left... Shaking with fear you eventually came out of your hiding place, grateful that you survived."
Lazy zombies
There are several situations that can lead to lazy zeds. Let me clear up some terms I'll use first.
Breach size refers to the zeds overflowing over your town's defense.
Attacking (atk) zeds refer to the number of zeds that actually attacked the town from your breach size. We have figured out how to predict atk zed number for specific cases. (see below)
And lazy zeds refer to the number of zeds that should have attacked but didn't. So breach size minus atk zeds equals lazy.
Okay! To understand lazy zed, you also need to understand how our attack algorithm works! If you're up for it, then continue.
The game has a pre-determined atk zed number for various range of citizens in town (# cit). These are simple rules that we figured out.
If #cit is 1 to & including 10, then expected atk zed = 150
For #cit between 10 to & inc 24 (not sure about 25), expected atk zed = 15*#cit
Here's where lazy zed comes in. If the breach size is larger than the expected atk zed, then the difference becomes lazy zed.
For example, SoB has 10 inside today, facing an overflow of 3,000 zeds. The expected atk zed is 150 for #cit=10. Since the overflow is greater than the expected atk zed, 3,000-150=2,850 will be lazy zed. The 10 at SoB is guaranteed to face 150 zed today.
What if the breach size is lower than the expected atk zed? Then all the breached zeds will attack! Take that example above with SoB, if the breach size is 145, then all 145, no lazy zed, will attack the 10 inside.
How about for when #cit is 26 or more? (we're not sure about 25) Can we also predict atk zed and lazy zed? The answer is no. The 15*#cit no longer predicts the atk zed. The atk zeds for #cit 26 or higher is always less than the predicted 15*#cit.
So 3 things we know when #cit is 26 or more
there will always be lazy zed, from the breach size (even for very low breach) the atk zed will always be lower than 15*#cit there is no obvious pattern relating breach size, atk zed, and #cit.
Hope this explains how the new attack algorithm works (as far as we know)!
Special messages
If, during an attack, zombies get in (it doesn't matter how many) and no one dies, it will be called "a miracle". If, during an attack, zombies get in and only one citizen die, it will be called "a stroke of luck"
What can I do during the attack?
During the assault, the game is inaccessible for 10-20 minutes, during which time a video will display instead, with two randomly chosen actions. Clicking either action refreshes the page and brings up other actions. There's no real value to this; just something to amuse yourself while waiting to see how your town fared.
List of actions:
- hug your rucksack
- scream
- wail like a banshee
- grind your teeth
- hug a broken guitar
- cry nervously
- scream and panic
- hide behind the wreckage
- hold the door
- wait under the sheets
- call for help
- yell “help”
- hide in a box
- hide under the bed
- wait calmly...
- curl up in the fetal position
- sing at the top of your voice, alone
- pray for your life
- clench your cheeks