Campaign
It starts as a power fault at a substation nobody cares about. The squad goes in on standard contractor rates, to a client that has already decided what happened. Then the doors open.
Around twenty rooms strung together with corridors, gates and bulkheads. There are vaults off to the side worth the detour, usually with something guarding them that thinks so too. It is a floor plan, not an arena.
Get somewhere. Clear a room. Cut isolators in the right order. Hold a corridor while the pumps drain, keep a tap alive, then fall back to the dock. The ones that pin a squad in one spot are the ones that hurt.
A bulkhead dropped behind a retreat holds for a while and no longer, and rolling one shut mid-fight is often the whole fight. No door can be closed onto the wrong side of an objective. The levels are built to stop that.
Five threat tiers sit on top of whatever the mission already asks, and each mission keeps a medal for the highest one it has been cleared on. Arm Last Rites (no revives, half the supply) and clear it on Terminal for a mark almost nobody has. The field manual covers the price.
All twenty missions play in four-player co-op, not just endless mode. The director scales the spawns to squad size, so four players get about two and a half times the volume rather than four times it.
Light spoilers from here. Mission names, locations, and roughly where each act ends up. Act I gets its briefings quoted. The later ones don't, for obvious reasons.
A tower full of people stopped answering the radio. The client says power fault, the contract says rescue rates, and the first room past the airlock says neither of those is right. By the end of the act, Kestrel gets written off with everyone still inside it.
The briefings are short. Mission one: "Kestrel Arcology stopped answering forty minutes ago. Meridian is calling it a power fault. Get into the substation, find out why the grid dropped, and get back out. Standard rescue rates." Mission three: "The growth is not spreading through Kestrel. It is being cultivated."
It got out. The metro carried it under six districts before anyone thought to close a street. The cordon around the old quarter went up with people still inside it. Meridian is loading something onto a ship under a false manifest, and Vesper wants proof the company knew, and somebody has to go and get it.
Meridian bought a mine forty years ago and never took an ounce of ore out of it, which leaves the question of what they were digging toward. The answer sits a few hundred meters down, and it is a great deal older than the company.
There is nothing left above ground to quarantine, so the plan gets simpler and a lot worse. A silo. A relay that stopped answering. A bunker full of the people who have been holding the leash this whole time. Then a caldera that has to be held while every infected thing on the continent walks toward it.
A mission does not retire once it is cleared. A level that was comfortable on Breach is a different job on Terminal, with nobody picking anyone up and half the ammunition on the floor. That is where the good drops are, and it is the only way the medal on that row changes.
The campaign comes with the full version. The demo is endless mode, with the whole loot and build system in it.