How to Play

Everything here is for Regular difficulty with the default match rules. The host can change difficulty, number of waves (or Endless), build time and more under Host Game → Match Rules.

The game in one paragraph

You and up to ~4 friends hold a small desert outpost. You start with nothing but the Command Post (CP), a Construction Allowance to fortify with, a shared pot of Supply for guns, turrets and support, and a few minutes to dig in. Then enemy waves attack from several directions, using smoke, suppression, sprinting assaults, demolition charges, armour, machine guns, marksmen and mortars against your defenses — and every 5th wave is a boss wave. Between waves you rebuild, extend the fort, reload turrets and argue about Supply. Survive the last wave and you win; lose the Command Post — or the whole squad in a wave — and you lose. Building a great fort makes you much stronger — but turrets are scarce, run dry and get smoked, and an unattended fort will fall. The defenses multiply the squad; they don't replace it. You have to hold it.

Co-op only: no friendly fire. Your bullets, turrets and wire only hurt enemies.

Maps (pick one in Host Game): Desert Outpost — a sandy basin, enemies come over the rim from ~70 m out, open ground with rocks and old fortifications. Village Crossroads — a bigger map: you hold the paved square in the middle of a desert village, enemies form up ~110 m out in the palm fields and fight their way in through streets, alleys, walled yards and gardens (lots of cover for them, long sightlines down the four main streets for you). Lanes: TOWN HALL (north), SCHOOLYARD (east), MARKET (west), WATER TOWER (south).

Controls (all rebindable: Settings → Controls)

Key	Action
W A S D	move
Left Shift (hold)	sprint
Space	jump (also stands you up from crouch / prone). Facing a ledge up to one wall high: climb it (hold it in a jump to grab one)
C / Z	crouch / prone
Q / E (hold)	lean left / right: peek around corners and over cover. Your head and upper body lean out with the view (enemies can hit what shows), walls stop the lean. Not while prone or sprinting
Mouse	look · LMB fire · RMB aim down sights (also closes menus)
R	reload · B fire mode (semi / auto)
1–9, mouse wheel	weapons (in menus: pick items; in build mode: pick structures / rotate)
G	tap = build mode on/off · hold = structure wheel
Left Alt (hold)	place without snapping
V	interact: hold to reload the turret you look at (4 s) · refill ammo at the Ammo Cache · open Tactical Support at the Support Radio you built · Backorder's shop (inside the Command Post)
X	switch the turret you look at on / off (save its ammo)
F (hold)	repair what you look at · defuse a charge · revive a fallen teammate (4 s)
Tab	scoreboard
Escape / F10	menu
F9	host: start now (while waiting for players) · restart the match (after it ends)

The match: phases and timers

Phase	Length	What you do	Shop	Build
Waiting for players	15 s, after the host's Players to Start have joined ("WAITING FOR PLAYERS 1 / 3"; host: F9 = start now)	friends join	✅	✅ (but nothing to spend yet)
Build phase	120 s*	the starter FOB appears (The base), 250 Construction + 150 Supply* arrive, 1 turret requisition. Fortify. Happens once.	✅	✅
Wave incoming	6 s	countdown banner with the wave's affixes (and boss)	❌	✅ last-second walls
Combat	until every enemy is dead	fight, reload turrets, repair, call support, revive the fallen (nobody respawns mid-wave)	❌	❌*
Wave cleared	5 s	wave reward paid (+ boss bonus), everyone who's down comes back	❌	❌*
Supply phase	60 s*	a Construction delivery + a new turret requisition arrive, the next wave's affixes (and boss) are revealed. Rebuild, extend, reload, re-arm.	✅	✅
Victory / Defeat	—	last wave cleared / Command Post destroyed or the whole squad down in a wave	—	—

* Host Game → Match Rules: Difficulty (Recruit / Regular / Veteran / Elite), number of waves (default 5, or Endless), build time, between-wave time, starting Supply, Build During Waves (lets you build in combat) and Players to Start (the match waits for that many players; default: anyone).

Player name: the first time you pick Host Game, Server Browser or Direct Connect, the title screen asks for the name other players see (never your PC name). Change it later in Settings → Gameplay.

Endless: there is no victory — survive as long as you can; waves after the 5th keep growing (+15 % enemies and +8 % enemy health per extra wave), and every 5th wave is a boss wave.

You lose when the Command Post is destroyed or when every player is down at once during a wave (nobody is left to revive anyone; after 3 s it's DEFEAT). Restart: the host presses F9 after the match.

The base

	What it is	If it's destroyed
Command Post (the container hut in the centre with the radio mast behind it and the radar truck alongside, "COMMAND POST" over the door, which faces the player spawn)	the objective, 4000 health. Backorder works inside it	you lose
Backorder (SSgt. Buck "Backorder" Mulligan)	the quartermaster's shop, inside the Command Post (walk in through the door), between waves only	— (he's fine. He's always fine.)
Ammo Cache	refill your ammo for 8 Supply — also during a wave	offline — no refills until repaired
Support Radio	you build it (structure wheel, 40 Supply, one at a time; a small comms trailer) — the Tactical Support terminal (Tactical Support)	gone — no support until someone builds a new one
Build zone	the 54 × 54 m area you may build in (posts mark it; outlined in build mode)	—

Starter FOB

The build phase starts with a free compound around the Command Post, so nobody starts from nothing:

a 30 × 30 m HESCO wall (one block high) with a 6 m gate in the middle of each side, facing each approach. The gates are deliberate: a fully closed compound makes the enemy blow their way in (Building), an open gate is a choke point you choose. Wire it, cover it, or narrow it.
sandbag cover just inside every gate, on both sides of the opening;
barbed wire across the north road in front of the north gate (wave 1 always comes from the north);
the Support Radio already built inside.

They're ordinary structures ("Builder: Starter FOB"): they take damage, can be repaired, stacked on and extended.

The ammo cache doesn't disappear when destroyed — it goes offline (red on the minimap) and comes back when repaired. The radio is a structure: destroyed means rebuild it. Enemies who get inside the wire may go for these instead of the Command Post, and sappers rate the radio right after turrets.

Sectors (attack lanes)

Enemies attack down four approaches. Each has a name you'll see on the HUD and a landmark you'll see in the world:

Sector	Landmark
NORTH ROAD	the road in, ruined checkpoint, old HESCO line	the main assault lane; wave 1 always comes from here
EAST TREELINE	broken line of trees	opens in wave 2
WEST WASH	rocky dry wash	opens in wave 3
SOUTH TRACK	concrete blocks along a track (behind your spawn)	from wave 4

A sign at the wire on each side names it. Callouts use these: "Contact east!", "West side breached!".

Each approach has four staggered belts of cover between the enemy spawns and your wire (HESCO pairs, concrete barriers, big rocks, sandbag ruins) — gaps everywhere, never a wall. The enemy uses them to advance (The enemy); you can use them as landmarks ("he's behind the HESCO on the east road") and as Artillery Strike targets.

Construction and Supply (two team resources) + your Dollars

Both are shared by the whole team, shown side by side at the top of the screen in different colours: CONSTRUCTION (orange) and SUPPLY (blue).

Construction determines the shape of the fortress. Supply determines the combat capability of the squad.

Construction Allowance — for building the fort

Pays only for passive fortification: sandbags, HESCO, wire, walls, window walls, doorways, floors / ceilings, ramps. It never buys turrets, ammo, attachments, support or repairs.

Delivery	Construction
Match start (build phase)	250
Supply phase after wave 1 · 2 · 3	125 · 150 · 175
After wave 4 and every later wave	200
After a boss wave	250 (the big shipment instead of the normal one)

No hoarding: when a delivery arrives only 25 % of what's left over carries on; the rest expires (e.g. 100 left + 150 delivered = 25 + 150 = 175). Spend it — that's what it's for.

Supply — for fighting

Pays for turrets, turret reloads, Backorder's shop (ammo, medkit, armor, weapon mods), the Ammo Cache, repairs and Tactical Support. Arguing about it is part of the game.

Income	Amount
Build phase	150
Kill: Rifleman 1 · Sapper 2 · Breacher / MG / Marksman / Medic 3 · Heavy / Officer 5 · Siege Heavy 40	per kill, whoever (or whatever) killed it
Wave cleared: 50 · 60 · 65 · 70 · 75 (75 for every wave after the 5th)
Boss wave cleared	+100 bonus on top of the wave reward

Every change shows briefly under the counters ("-40 COUNTER-BATTERY", "+5 HEAVY KILL", "CONSTR. -15 HESCO BARRIER", "CONSTR. -38 EXPIRED ALLOWANCE"). Not enough → "Insufficient Supply" / "Insufficient Construction" and nothing is charged.

Dollars — your own money

Unlike Construction and Supply, Dollars belong to you. Everyone starts the match with $200 (also when joining late) and earns more by doing the work. They don't buy anything yet — they're being saved up for personal kit upgrades later. Your Dollars show in green next to your name above your vitals; the scoreboard shows everyone's.

You…	Dollars	Score
kill an enemy	$25 + a bonus for special enemies: Sapper +5, MG / Marksman +12, Breacher / Medic +15, Officer +20, Heavy +30, Siege Heavy +200	100 + bonus (Sapper 25, MG / Marksman 60, Breacher / Medic 75, Officer 100, Heavy 150, Siege Heavy 1000)
kill one with a turret / wire you built (defense kill)	$15 + the same bonus	75 + the same bonus
build a structure	$5	10
repair (structures, infrastructure, Command Post)	$5 per 100 health	10 per 100 health
revive a teammate	$50	50
reload a turret	$10	20
defuse a charge	$40	75
survive a wave (everyone)	$100	100
deal damage to enemies (you or your structures)	—	5 per 100 damage (+10 per 100 on a boss)

Every payment pops up right of the crosshair for a few seconds ("+$40 +100 BREACHER KILL", "+$7 +14 HESCO BARRIER REPAIR"). The team's Supply income from kills and wave rewards is unchanged — Dollars come on top.

Building

G (tap) = build mode, hold G = structure wheel. Aim, mouse wheel rotates, LMB places, RMB leaves. Allowed in the waiting / build / supply phases and the 6 s countdown (not in combat unless the host allowed it).

Piece	Cost	Health	Notes
Sandbag Wall	5 Construction	600	stops bullets; stacks on / beside other blocks
HESCO Barrier	15 Construction	2500	the toughest block; stack them for walls and towers
Barbed Wire	10 Construction	250	enemies who walk into it get snagged (near standstill for 1.5 s), then push through at 25 % speed — no sprinting in the wire — taking 4 damage/s and trampling it
Auto Turret	65 Supply + 1 requisition	500	limited — see Keeping the fort alive
Wall / Window Wall / Doorway	8 Construction	1500 / 1200 / 1200	snap to a 2.5 m building grid
Floor / Ceiling	10 Construction	1500	needs walls or ground under it
Ramp	10 Construction	1200	up one storey
Support Radio	40 Supply	1200	Tactical Support terminal (Tactical Support); one at a time; the enemy hunts it

The first piece goes anywhere; others snap to what you aim near (on top, beside, along the grid). Hold Left Alt to place freely.
Blocks (sandbags, HESCO) stack: aim at the top or the upper part of a side to go on top, the lower part of a side to slide in underneath (when there's room), the middle of a side to go beside it.
Rules: inside the build zone, within 9 m of you, ground not steeper than 30°, base no higher than 7.6 m, must rest on something. Pieces may overlap each other — but not the Command Post or Backorder.
When a piece is destroyed, anything that was resting only on it collapses.
The build bar and wheel show each piece's cost and which resource it uses (orange = Construction, blue = Supply), health and what it's for. The turret also shows turrets active / allowed, the requisition, ammo, range and arc.

Good to know: enemies who can't path to the Command Post break through the wall in the way. Fully enclosing the CP doesn't stop them — it makes them break in. Choke points work; plan for them to be attacked. They climb, too: about half the riflemen, heavies, medics and officers climb over a wall in their way when it's only one wall high (a single HESCO, sandbags, a single wall), instead of shooting through it — slowly, and they can't shoot while doing it, so it's a good moment to catch them. Stack it two high (two HESCO, three rows of sandbags) and nobody climbs it: they have to break through.

Keeping the fort alive

Damage stays

Nothing heals by itself between waves. Look at a structure to see its health, builder and the cost of a full repair.

Repair — hold F

Look at a structure, turret, the radio, the ammo cache or the Command Post and hold F (within ~4 m).

Restores 8 % of its health per second (at least 40 HP/s). You can't shoot while repairing.
Costs Supply as you go (never Construction): a full repair from nothing costs 60 % of the piece's price (sandbags 3, HESCO 9, wall 5, turret 39, radio 24). Ammo cache: 30 for a full repair. Command Post: 80 for all 4000 health.
Stops when you let go, step away, it's full, or Supply runs out.
You can repair mid-wave. You're standing still, exposed. That's the price.

Turrets: powerful, scarce, and they need you

Turrets are force multipliers, not soldiers. They are limited four ways:

Team cap (standing turrets, the whole team): 1 in wave 1, 2 in wave 2, 3 from wave 3. "AUTO TURRETS 2 / 3 ACTIVE".
Requisition: a new turret needs 65 Supply + 1 turret requisition + a free slot. You get 1 requisition per build / supply phase, and they don't stack (max 1). Destroyed turrets free their slot, but nothing is refunded — protect them.
Firing arc: a turret only covers 150° around the way it was placed facing (it faces away from you when you place it; mouse wheel turns it). While placing you see its arc, range (35 m) and a facing arrow on the ground; looking at a built turret shows the same. Anything outside the arc walks past it.
Ammo: a belt is about 45 s of sustained fire. Empty = silent: "TURRET OUT OF AMMO", "NO AMMO [V]" over it.

Reload: look at it and hold V for 4 s next to it. Costs 10 Supply, charged once when the reload completes (let go or walk away and it's cancelled, nothing charged). It doesn't fire while being reloaded. X switches a turret off / on: off it holds fire and saves ammo (e.g. the north turret while the attack is east — switch it back on when they shift north). The look panel shows HEALTH, AMMO, MODE (ACTIVE / DISABLED / RELOADING), BUILDER, [hold V] Reload — 10 Supply, [X] Disable Turret, "OUT OF AMMO", "INSUFFICIENT SUPPLY".

The enemy fights turrets (see The enemy "The enemy fights back"): a busy turret draws attention — smoke gets thrown between it and the assault, riflemen shoot it from outside its arc or from cover, heavies walk into its fire on purpose to drain the belt, sappers make it their first target, marksmen pick off whoever is reloading it, mortars like turret clusters. Turret rounds barely scratch heavy armour. Kills by your turret (and wire) count as your defense kills.

Your soldier

Health 100, helmet (40) and plate carrier (120). Armor stops or blunts bullets and wears down; Backorder sells fresh plates (15) and a medkit (10, back to full health).
Weapons: 1 M4 carbine (5.56, 30 rounds, semi / auto), 2 Glock 17 pistol (9 mm, 17), 3 M200 sniper rifle (.408, 7 rounds, bolt action: ~1.5 s between shots, heavy recoil, slow to aim, but 0.5 MOA and 125 damage). R reloads from your reserve; refill reserves at the Ammo Cache (any time) or Backorder (between waves).

Weapon mods (Backorder → Weapon Mods, between waves): every gun has slots, and each mod fits only some guns. Unlocking a mod costs team Supply once — after that it's yours for the match: swap it on / off any gun it fits for free (respawns keep your setup). The screen shows each change (green better, red worse) before you pick.

Slot	Mods (Supply to unlock)	Fits
Optic	Iron Sights (stock) · Red Dot 1× (15) · Pistol Red Dot 1× (10) · 2× Sight (20) · 3× ACOG (25) · 6× Scope (30)	red dot: rifle / sniper · pistol dot: pistol · 2× / 3×: rifle / sniper · 6×: sniper only
Barrel	Suppressor (20): 30 % loudness, almost no flash, a bit slower to aim · Compensator (15): −40 % sideways kick, −8 % climb · Muzzle Brake (15): −30 % climb, louder, bigger flash · Flash Hider (10): −75 % flash	suppressor: all · compensator: rifle / pistol · brake, flash hider: rifle / sniper
Underbarrel	Vertical Grip (15): −20 % climb · Angled Grip (15): −25 % sideways kick, +12 % aim speed	rifle
Magazine	Extended (15): +50 % rounds, +15 % reload time · Fast Mag (15): −30 % reload time · Drum (25): double rounds, +45 % reload, slower aim	all · drum: rifle

The M4 starts with a Red Dot, the M200 with the 6× Scope (it has no iron sights, so it always keeps an optic). 2× / 3× / 6× optics follow Settings → Gameplay → Scope Style: Picture-in-Picture (the zoom shows inside the lens, you still see around it) or Full Screen (the whole view zooms, everything outside the scope goes black, duplex reticle). Zoomed views turn slower to match the zoom, so aim stays steady.

Sprint (hold Shift): 1.6× speed, about 6 s of stamina (bar under your health); recovers after a second.
Stance: crouch (C) and prone (Z) make you smaller and steadier; jump stands you up.
Climbing: look at something up to one wall high (2.5 m: a HESCO, one or two rows of sandbags, a wall, a roof edge on one storey) and press Space: you pull yourself up onto it — or, when it's too thin to stand on (a wall), over it and drop down the other side. Pressed mid-jump, you grab the ledge as soon as it's in reach. Takes about half a second to a second (higher = longer); you can't shoot or aim while climbing. Two HESCO, three rows of sandbags or two storeys are too high. Standing up only — jump stands you up first.
Suppression: machine guns and marksmen firing at you darken the screen edges, make your aim drift slightly and widen your spread (up to 1.8×; "SUPPRESSED" when heavy). It wears off fast once they stop. Get behind cover.
Death: during a wave nobody respawns. A teammate can pick you up: they look at your body and hold F for 4 s ("MAN DOWN — hold F on them to revive", the body is a look target like a structure) — you're back where you fell with half your health and a fresh loadout. Otherwise you're back when the wave is cleared. Outside combat you respawn after 3 s. The No Medevac affix turns revives off for its wave. If the whole squad is down at the same time for 3 s, the match is lost ("The squad was wiped out").
Spectating while down: LMB watches the next teammate still standing, RMB the previous one, Space goes back to your own body (uses your Fire / Aim / Jump keys). The camera sits over their shoulder and follows their aim; if they go down it moves on to the next one (or back to you when nobody is left standing). You return to your own view the moment you're revived or respawn.

The enemy

How waves attack

Each wave the enemy spends a budget (bigger every wave, scaled by difficulty and the number of players) on a mix of soldiers, and picks an attack plan: everything down one road, a pincer from two sides, a small push to pull you one way before the real attack hits elsewhere, attacks from three or four sides, a smoke-and-breach assault, a slow siege with machine guns and mortars, or a fast raid on your turrets. You don't see the plan — you see where they come from: watch the alerts, compass, minimap and base status.

Lanes open up over the match (The base). Well defended sides are attacked a bit less often — never never.
When a lane becomes a meat grinder (a group losing most of what it sent), the enemy adapts — but not always the same way: roughly 30 % keep pushing, 25 % shift the rest to a weaker lane ("NEW CONTACT — EAST"), 20 % split into a pincer, 15 % regroup on the same lane with smoke and sappers ("ENEMY REGROUPING"), 10 % go somewhere random. Building well is never punished by always hitting your weakest side. Nobody teleports: only enemies that hadn't arrived yet change route.
Up to 40 enemies at once; the rest wait their turn.

The enemy fights back

Enemies aren't bullet sponges — they react to your fire:

Suppression: your bullets don't have to hit. Rounds cracking past them (within ~1 / 3 / 5 m), hits and your explosions pile up suppression. Pressured: their aim gets worse. Suppressed: they look for cover and sprint to it, firing less. Pinned: they stay behind cover and stop shooting until it wears off, then peek and push again. Heavies shrug most of it off; the Siege Heavy ignores it.
Cover: they pick nearby spots your shooter can't see (walls, terrain, smoke), preferring ones that still move them forward and staying out of your other turrets' arcs — and crouch behind it.
Sprinting: they run (riflemen ~1.6×, sappers ~1.7×, heavies ~1.25×) to cover, out of a turret's sight, through smoke, at a breach, and on the final rush at a wall or the Command Post — in short dashes, not constantly.
They remember who's shooting them — a turret or a player — and answer it: smoke for turrets, cover from riflemen. Hiding behind three turrets doesn't work: they drain the belts, smoke them, break in and blow them up.
Two kinds of attacker: about half are careful — once under fire or inside a turret's reach they advance from cover to cover along the approach (dash, crouch a second, peek, dash). The rest are aggressive and push straight in, sprinting through danger. Every attacker has a deadline (30–55 s after it arrives): after that even the careful ones stop hopping and assault. Waves keep moving — no endless standoffs.
Nobody hides forever: an attacker that hasn't fired, hit anything or been hit for 25 s stops hanging back and assaults the base, sprinting. When nothing is left to spawn and 3 or fewer remain, they all assault — and show on your minimap, so you don't have to hunt for the last ones.
They climb low walls: about half of the riflemen, heavies, medics and officers walk up to a wall that's in the way (one wall high at most) and climb onto or over it, then drop down your side, instead of breaking through. Sappers, breachers, machine gunners and marksmen never climb. Nothing climbs two blocks high.
Get too close and they fight: a defender within ~15 m and in sight gets an immediate reaction — they come out of cover, stop sprinting and shoot, even when suppressed (and through thin smoke at very close range).
Name tags: you don't know who's who until you hit them. A special enemy's role tag (BREACHER, MEDIC, MACHINE GUN…) appears when the squad lands a shot on it and fades 5 s after the last hit; every new hit resets it. Recon Sweep shows everyone's tags. "PLANTING CHARGE!" is always shown.

Who's coming (and how to deal with them)

There are no markers over their heads: every type has its own uniform colour, headgear, kit and gun, and some are bigger. Special ones also get a name tag over their head once you've hit them (see "Name tags" above).

Enemy	Looks	Does	Counter
Rifleman	bright green, cap or boonie hat, assault rifle	advances, shoots defenders, breaks walls in the way	everything
Heavy	big (1.25×), olive drab, helmet, auto shotgun	slow, very tough, hits structures hard	focus fire; turret rounds barely scratch the armor
Sapper	desert tan, goggles, satchel on the back, small SMG	goes for turrets, then the radio / ammo cache, then walls; plants small 4 s charges. Once it has an open way to the Command Post it skips walls and charges the Command Post instead	kill them early; defuse
Breacher	rust red, goggles, big satchel, pump shotgun	picks a wall on its side, kneels 3 s ("PLANTING CHARGE!") then an 8 s breach charge that blows the wall open. If there's already a way in (a gap, or it's inside the wire) it goes straight for the Command Post and plants it there	kill it while it kneels, or hold F on the charge (2.5 s) to defuse
Machine Gunner	slate blue, helmet, long battle rifle	sets up ~35 m out and fires long bursts (~800 rounds a minute, 12–22 rounds, short pauses) that suppress you; with nobody visible, it rakes your walls	stay low between bursts, flank it, or smoke it
Marksman	dark brown, boonie hat, backpack, scoped rifle	70 m, slow and accurate; prefers defenders up on walls / towers and ones standing still	keep moving, don't skyline yourself
Medic	all white, red cross on the helmet, SMG	heals attackers around it	kill it first
Officer	black uniform and cap, SMG	nearby attackers move faster and shoot straighter	kill it first
Mortar team	off the map	see below	Counter-Battery
Siege Heavy (boss)	a giant (1.6×) in crimson with a helmet and an anti-materiel rifle	very armoured, slow, smashes walls (380 per hit), turret rounds do a third of their damage	everyone focus fire — aim for the limbs (unarmoured)

Enemies stop moving once the match is over. On early waves you'll mostly meet riflemen; specialists join from wave 2–4.

Smoke

Enemies throw smoke across your defensive line as they close in ("ENEMY SMOKE — NORTH ROAD — Smoke north! Watch the gaps!"), and right in front of a turret that's chewing them up ("SMOKE ON TURRET — They're smoking the turret! Eyes up!") — riflemen pinned by a busy turret get handed a grenade for exactly that. Smoke lasts ~25 s. Inside or behind it:

your turrets can't see (they go quiet),
enemies can't see you either (both ways),
sappers and breachers like to come through it.

Answer: get eyes and guns on the gap, or call friendly smoke (it blinds them, not your turrets).

Breach charges

"BREACHERS SPOTTED" when they arrive; "BREACH CHARGE — EAST HESCO BARRIER" (magenta, countdown, arrow, beeping) when one is planted. 8 seconds. Kill the breacher before it finishes kneeling, or defuse (hold F on the charge, 2.5 s). If it goes off: "WALL BREACHED — plug the gap!" — on Regular and above one charge destroys any single wall piece (even a full-health HESCO).

Mortars

From wave 3 (sometimes, more with Fire Support / Siege): "ENEMY MORTAR BATTERY DETECTED — EAST" and a distant thump every time it fires (~every 14 s). Each round:

a red pulsing ring on the ground where it will land (on screen and on the minimap) — 3.5 s before impact,
an incoming whistle in the last ~2 s, "INCOMING!" if you're near,
600 damage to structures (a direct hit flattens a sandbag wall, four take down a HESCO, one can kill a turret), 85 to players at the centre (less at the edge). Ignoring a mortar battery gets expensive fast.

Rounds love turret clusters, the radio and ammo cache, and players standing around inside the wire. Never unavoidable — move out of the ring. Stop the battery with Counter-Battery (Tactical Support).

"They're inside"

The first enemy inside the build zone on a side: "THEY'RE INSIDE — WEST WASH" and, once per wave, a big banner. That's not game over — it's a new phase of the fight. Fall back, protect the Command Post, the radio and the ammo.

Tactical Support

Build a Support Radio first (structure wheel, 40 Supply). Walk to it, look at it and press V. Pick a row (click or number key), press again or click YES to call it. Lane strikes need a lane: click NORTH / EAST / WEST / SOUTH on the little map (it starts on the busiest one). Each row shows the price, your Supply, the cooldown or "on the way" timer, and why it can't be called right now. The radio operator confirms it ("Fire mission requested, stand by") and Backorder complains about the bill.

Support	Cost	Arrives	Cooldown	Does
Counter-Battery	40	10 s	45 s	destroys every enemy mortar battery (only when mortars are active)
Recon Sweep	20	2 s	45 s	for 25 s: what's coming down every lane, special threats, enemy tags through walls
Emergency Ammo	30	4 s	60 s	every turret's belt and everyone's ammo refilled
Artillery Strike	75	7 s	90 s	8 shells on one approach (never inside the wire). Hurts — won't clear a wave on its own
Smoke Barrage	25	3 s	40 s	friendly smoke on one approach for 30 s: blinds them, not your turrets

Strike, Smoke and Counter-Battery only during a wave. No radio standing = no support ("No Support Radio - build one").

Affixes

Each wave rolls affixes (13 in the pool): 1 on wave 1, 2 on wave 2, 3 on wave 3, 4 on wave 4 and every wave after (Endless too; boss waves always have 4). They're revealed at the start of the phase before the wave — big banner plus the preparation panel on the left listing every affix with its one-line description — so you can adapt the fort. No affix twice on one wave; every affix is used once before any repeats. Some don't mix: at most one visibility affix (Fog or Blackout — Smoke Screen can still join either) and one economy affix (Crisis or Windfall).

Affix	Category	Effect
FOG	visibility	thick fog; enemies only open fire at about half range — but you won't see them coming either
BLACKOUT	visibility	night assault: the lights go out, enemies open fire at 60 % range, your turrets see only 70 % as far
SWARM	assault	many more, much weaker riflemen, arriving faster; fewer heavies
COMMAND STRUCTURE	assault	at least 2 officers and a medic, more of both — kill the leaders first
TOTAL WAR	assault	+20 % attackers, arriving faster, plus an extra mortar
SAPPERS	defense counter	lots of sappers and breachers — defend the fort itself
SMOKE SCREEN	defense counter	every group brings more, bigger, longer-lasting smoke; sappers advance behind it
HEAVY METAL	armour	at least 2 heavies, three times as likely — turret rounds bounce off
FIRE SUPPORT	support	more machine gunners and marksmen, an extra mortar, faster mortar fire
NO MAN'S LAND	mobility	attackers 15 % faster, sprint longer, and wire slows and snags them only half as much
SUPPLY CRISIS	economy	repairs, turret reloads, Backorder's prices and the ammo cache cost 40 % more; the wave pays 30 % less
SUPPLY WINDFALL	economy	kills and the wave reward pay 50 % more
NO MEDEVAC	logistics	nobody can be revived this wave — the fallen are back when it ends

Boss waves

Every 5th wave (5, 10, 15…) is a boss wave: a coordinated siege built around one boss threat, on top of the normal attack and 4 affixes. The supply phase before it says so loudly: "BOSS WAVE INCOMING — THREAT: SIEGE HEAVY", with the threat, a warning and the affixes, and the preparation panel turns red.

Siege Heavy (the first boss): arrives ~25 s into the wave down one lane, escorted by riflemen with smoke and sappers following it into the breach. 2400 health (more on later boss waves), heavy armour on the chest and head, slow, can't be suppressed, smashes walls in its way toward the Command Post and wades into busy turrets. Turret rounds do a third of their damage. A boss health bar appears at the top while it's on the field; "SIEGE HEAVY INBOUND" when it shows up, "SIEGE HEAVY DESTROYED" when it drops. Answer: focus fire (limbs are unarmoured), keep sappers off it, repair the wall it's hitting, Artillery Strike it on the way in.

Reward: clearing a boss wave pays +100 Supply on top of the wave reward, and the next Construction delivery is the big 250 shipment — waves 1–4 escalate, wave 5 is the siege, then you rebuild.

Difficulty

	Enemy health	Enemy numbers	Enemy damage	Enemy accuracy / fire rate
Recruit	×0.75	×0.7	×0.5	much worse / slower
Regular	×1	×1	×1	normal
Veteran	×1.25	×1.3	×1.25	better / faster
Elite	×1.6	×1.6	×1.6	much better / faster

The enemy also scales with the number of players (counted when each wave starts): every player after the first adds 50 % more attackers — 1 player ×0.6, 2 ×1.1, 3 ×1.6, 4 ×2.1, 5 ×2.6, 6 ×3.1. At most 40 are on the field at once; the rest arrive as others fall.

Reading the screen

Where	What
Top centre	compass with the four lanes in their state colour · the boss health bar under it while a boss is up · short banners (wave starting, affix reveal, boss) — one line, a few seconds
Left, between waves — preparation panel	WAVE n PREPARATION: time left, Supply, Construction, turrets active / allowed, turret requisition (AVAILABLE / USED), every affix with its description, the boss (red) on boss waves
Top left — base status	the match at a glance: wave, phase + timer (or enemies left), Command Post bar ("HIT!" when it's being hit), Construction (orange) and Supply (blue), turrets active / allowed, the wave's affixes during combat. Then each sector: SECURE (green) · INCOMING (yellow) · UNDER ATTACK (orange, enemies at the wire) · BREACHED (red, inside) · enemy count · MORTARS · Support Radio (health, or NOT BUILT) and ammo cache health. During Recon: what's on each lane. The Construction / Supply feed runs beside it
Top right — minimap	north up, the fort in the middle: lanes in their state colour, walls, turrets (cyan, red = empty), radio (blue), ammo cache (orange), CP (gold), you (arrow), team (green), enemies you can see, smoke, incoming mortar rings, charges
Under the minimap — alerts	the most important first; red = critical (breach charge, breached, mortars) with countdowns
Bottom left — squad (above your vitals, only with teammates)	every teammate: name, health % + bar, armor (thin blue line), DOWN (red) or REVIVING % (green), distance to them; header "n / m UP" turns red when someone is down
Bottom — radio subtitle	the radio operator's callout ("Contact east!") · Backorder's lines above the weapon bar
Bottom left — vitals header	your name and your Dollars (green)
Just right of the crosshair	your own rewards as you earn them: "+$25 +100 KILL" (Dollars green, score gold)
Right of the crosshair	whatever you look at: name, health %, builder, turret ammo / mode, repair cost, [hold V] / [X] / [hold F]
Over a teammate you aim at	their name (green), distance past 10 m, health bar and armor line; fades half a second after you look away. Walls hide it
In the world	ground rings (mortars), arrows at the screen edge (breach charges, critical alerts), enemy role tags (only after you hit them), turret warnings (LOW AMMO / NO AMMO / OFF / RELOADING %), a turret's arc + range on the ground when you place or look at one, build-zone outline (in build mode)
Screen edges darken	you're suppressed
Dead	"KILLED IN ACTION" with what happens next: wait for a revive (or the end of the wave), BEING REVIVED %, or NO MEDEVAC; "[LMB] / [RMB] Watch a teammate" while someone is still up. Watching: "SPECTATING <NAME>" band near the bottom with the same status and the cycle keys

The radio operator calls every important event out loud; Backorder comments on purchases, support calls, wave ends and the match result.

Winning, losing, score

Victory: clear the last wave. Defeat: the Command Post is destroyed, or the whole squad is down at once during a wave (Endless always ends one of these ways).
Score (scoreboard, Tab — bragging only, it doesn't buy anything): everything that pays Dollars also scores — see the table in Construction and Supply (kills, defense kills, building, repairing, reviving, turret reloads, defusing, surviving a wave, plus damage dealt and boss damage). Scoreboard columns: kills, streak, best, defense kills, deaths, builds, revives, damage, cash (Dollars on hand), score and ping (each player's round trip to the host in ms — green under 80, amber under 150, red above; the host shows 0).
Kill streaks: your streak counts kills since your last death (KILLS / STREAK / BEST above the weapon panel, STREAK / BEST columns on the scoreboard). Kills within 4 s of each other chain into DOUBLE / TRIPLE / MULTI KILL; streaks of 5 / 10 / 15 / 25 get a callout. The team kill feed (left side) shows everyone's kills and streaks. Bragging only, like score.
Host: F9 after the match = new match on the same map; everyone stays connected.

Glossary

Supply — the team's shared money for fighting. Construction (Allowance) — the team's building budget, refreshed every break, only 25 % carries over. Requisition — permission to field one new turret (1 per break). Suppression — how pinned down an enemy (or you) is. Boss wave — every 5th wave. CP — Command Post. Lane / sector — one of the four approaches (North Road, East Treeline, West Wash, South Track). Affix — the wave's special rule. Breach — a wall blown open, or enemies inside the wire. Belt — a turret's ammo. Counter-battery — artillery against their mortars. Defense kill — a kill by something you built. Backorder — the quartermaster; complains, sells things.