Survival

• Everyone plays on one side: the lobby is a single Allies list. You keep your own faction and color picks, and AI allies fill any empty seats.
• Your half is the full Regular game — income, lumber, spawners, researches, the shop, rescue strikes, and your army waves marching as normal.
• The enemy has no player and no castle. A wave director runs an authored attack schedule against you, escalating from trash packs to heavier set-piece waves as the clock runs down.
• Enemy waves scale with your player count, so a full Allies list faces a proportionally bigger horde.
• Victory: the timer reaches zero and your castle is still standing. Defeat: your castle falls. Nothing else ends it.

The gap between enemy waves is your build window. The early schedule is a formality; the late schedule is not, and the last stretch is a race between your economy curve and the director's. Co-op turns it into a coordination game: who covers anti-air, who holds the lane, and who saves a rescue strike for the wave that goes wrong.