The Dead Don't Rest
Co-op zombie survival
Fight through a zombie-overrun valley. Its NPC system lets you intervene to save survivors trapped on top of cars or barricaded in buildings - rescue them and they hand over special loot. Other NPCs roam the valley too: some friendly, some not.
Building now: four bosses - the Ringmaster, Scarecrow, Stadium Mutant, and a zombie Principal in a school; new weapons (knife, nailed bat, crossbow, shotgun); and upgraded fireworks / flare / glow-stick effects.