The Fight
When something comes through the door, the game changes shape but it does not change engine. You are still rolling 2d6 plus a skill rating against a target. What changes is that the room now has a clock on it.
Exchanges
A fight runs in exchanges of about ten seconds. There is no initiative and no turn order to wait through. Each exchange the GM reads the tell — the sound the thing makes before it arrives — and then everyone declares one action, in whatever order you can agree on among yourselves. Everything resolves at once. Two of you shooting the same thing both roll, and the damage adds.
Then contact happens, then the horde's escalation wheel turns one notch, and then you do it again.
You get one action. You also get whatever the fiction gives away free — talking, dropping something, looking at what everyone else is looking at. Reloading is an action. That is the single most expensive fact in the system and it is why Speed Cola costs 45 points.
If you have not declared by the time the table moves on, you are hesitating. Hesitating is not free.
Hitting things
The target number comes off the threat itself, not off the GM's mood. Rating 1–3 is Routine, 4–6 is Tricky, 7–9 is Hard, 10 or more is Desperate. You can ask what band you are rolling against and the GM will tell you.
On a success, your weapon's damage rating comes off the thing's toughness. At zero it is down and it stays down.
Surplus damage carries to the next body in the line. This is the rule that makes weapon choice a real decision. A rifle that deals four into a shambler with three toughness has a point left over, and that point goes into the one behind it. A shotgun in a doorway is genuinely two bodies. A pistol is not.
A natural 12 doubles the damage. A natural 2 misses and jams the weapon, and clearing a jam is an action you did not want to spend.
Ammunition is not counted bullet by bullet. If you fired in a scene, the crew's shared ammunition pool drops by one at the end of it. At zero, every shot is a band harder and you are fighting with what is bolted to the walls.
The line, and why doorways matter
A crowd of shamblers is run as a line, not a mob. However long the line is, only the front two are in contact with you.
That one sentence is the tactical heart of this game. A doorway means two. An open yard means everything. Every good decision anyone makes in a fight comes back to it, and the crawlers, the hounds and the armour exist specifically to take your doorway away.
On the map
If the GM puts a map of the room down, you are on it. The pins are the machines and the points of interest, the areas are the rooms, and the grid is just the ground made countable. Positions are real — a doorway is a position you can hold, the open yard is a position everyone can see you in, and "in contact" means on the map within reach. The tell, the line, and the doorway all live on the same floor you are standing on. If the GM is not using a map, none of this changes — the map is a convenience, not a rule.
Getting hit
Nothing rolls to hit you. At the end of every exchange, anything still standing within reach costs you wounds automatically: one for a shambler or a sprinter, two for a beast or armour, three for a set-piece.
There is no dodge roll. The dodge was the action you spent at the start of the exchange, and if you spent it on something else you chose to be bitten. You will do this, and you will do it on purpose, and that choice is the game.
Your wound threshold is 3 plus your Brawn, plus 2 while you hold Juggernog. Against two wounds a contact, an unbuffed character is two bad exchanges from the floor. That maths is not an accident.
Room Left comes back at one point per full scene out of contact, and all of it at a full rest somewhere secure. There is no healing during a fight. If you want to be whole, you have to leave — and leaving costs the clock.
Going down
At zero Room Left you are Down. Down is not dead. Down is the count before it.
You are on the floor. No actions, no rolls, you can still talk. You are Bleeding. The GM starts a bleed-out clock of three exchanges where everyone can see it, and when it fills, you die. Quick Revive makes it four.
Somebody reaching you spends a whole exchange on it — Medicine at Tricky, or Hold Fast at Hard if nobody has a medic's hands. You come up with 1 Room Left, still Bleeding. A failure fills another segment. With Quick Revive the whole thing is a single action and you come up on your feet.
While you are down you take no more wounds; there are none left to take. What you cost the crew instead is worse. The thing standing over you stays there, and everyone who comes to help walks into it.
You die when the clock fills, or if you go down a second time before recovering a point of Room Left. Nothing else kills you. It will happen because somebody held a door or went back for a body, and that is the only kind of death this system is interested in.
What to do about it
Move. Fight in doorways. Buy Juggernog before you buy anything clever. Reload before you need to, because you will not get the exchange later. Go back for people, and understand exactly what it costs when you do.
And know which round you should have left — the GM will tell you, loudly, and you should believe them.