No Rest Below

Pollution has swept across the surface, turning most of humanity into zombies.Lead a small band of survivors underground and rebuild a shelter within an abandoned facility. But underground does not mean safe. The hordes are closing in, and the next wave won’t wait for you to recover.

Hold the Line

Arm your survivors and fortify your shelter’s entrance with barricades, automated turrets, and defensive structures. Build a line of fire strong enough to stop the advancing dead.

But a defense that holds now may not survive the next wave. Special zombies can heal nearby enemies, strengthen the horde, spread toxic zones, or bypass conventional defenses, forcing you to rethink your firepower and defensive positions.

The next wave can arrive before you’ve finished clearing the last. If you feel ready, you can even call it in early, earning extra resources in exchange for the risk of fighting overlapping waves.

Hold your ground or invite more trouble? Every decision can build your advantage—or bring your defenses down sooner.

Build Your Shelter

Construct production facilities to maintain your resources and power supply. Fortify the entrance with barricades, automated turrets, and defensive structures to create your own defensive line.

Every resource spent is a choice between further expansion and preparing for battle. Expand too quickly, and your defenses may not be ready in time. Invest too heavily in defense, and your shelter may struggle to grow.

Manage Your Survivors

Assign residents to production, construction, repairs, and defense. Equip them with weapons, and give exhausted survivors time to rest.

Build a Worker Robot Hangar to put tireless robots to work in non-combat roles. They can ease the pressure on your workforce, but the survivors holding the line will still grow tired—and still get hurt.

Return Stronger

Kill zombies and collect Crystal Cores with different rarities and modifiers. Equip them to facility types to strengthen every facility of that type. From damage, attack speed, and range to durability, shields, and production output, combine cores within limited slots to shape your shelter and defensive strategy.

Even when your shelter falls, you’ll earn Crystal Cores and progression resources based on the highest wave you cleared. Unlock permanent upgrades and open up new paths for your next attempt.

Build, upgrade, fall—and return underground with everything you’ve gained. How many waves will your shelter survive this time?

When Everything Goes Wrong, Press the Button.

When production stalls, defenses crumble, and the horde is about to break through, you can activate Emergency Mode.

Override the normal work-and-rest cycle and push your entire shelter to operate more efficiently—but rapidly drain your residents’ stamina in the process. How long you keep it active, and when you switch it off, can decide whether you turn the battle around or leave your entire workforce exhausted before the next wave.

Every second buys you time now at the cost of what comes next.