Dome Keeper: How to Beat the Acid Rain Assignment

To beat the Acid Rain assignment in Dome Keeper, you must counter constant ambient surface corrosion by prioritizing early shield upgrades, carving straight vertical mining shafts, and saving all cobalt for emergency combat repairs.

Under the Acid Rain modifier, your dome sustains continuous passive damage even between enemy waves. If your shield breaks, atmospheric corrosion burns directly into the dome hull, draining repair materials before late-game waves arrive.

Managing the Acid Rain Hazard

In standard runs, the time between waves allows unpressured mining and resource collection. During an Acid Rain assignment, that downtime continuously drains dome health unless an active barrier absorbs the decay.

• Rush Shield Regeneration: The Shield generator and its recharge upgrades are mandatory. A rapidly recharging shield completely absorbs ambient corrosion, preventing hull deterioration between waves.
• Preserve Cobalt for Catastrophes: Never spend limited cobalt to patch minor environmental decay. Reserve cobalt exclusively for critical structural damage sustained during monster assaults.
• Minimize Surface Exposure Time: Lingering inside the mine without returning resources delays critical defense upgrades. Monitor the wave timer closely to ensure you are back at the turret before enemies arrive.

Early Mining and Upgrade Order

Early survival depends on turning initial iron into rapid movement and excavation speed. Stalled mining directly translates to environmental hull damage.

1. Drill Upgrade 1: Spend your first iron haul immediately on your drill. Clearing the first rock tier in fewer hits preserves shield integrity overhead.
2. Carry Capacity and Move Speed: Upgrade carrying strength immediately after the drill. Dragging heavy mineral bundles up long tunnels leaves your base vulnerable.
3. Carve a Central Drop Shaft: Drill straight down from the dome foundation to create a vertical drop line. Branch horizontally only along visible resource seams so mined ore falls directly to the main path for quick collection.

Avoid clearing isolated, off-path single tiles early on. Digging dense rock without matching drill power wastes valuable seconds while acid damages your exterior.

Defensive Upgrade Priorities

Use your mid-tier resources according to how directly each upgrade mitigates continuous decay:

Combat Targeting and Relic Extraction

Monster assaults overlap with the acid storm, making fast target prioritization essential during defense cycles:

• Eliminate Aerial Threats First: Fast flyers and ranged spitters strip shield energy rapidly. Sweep turrets across flying clusters as soon as they enter the screen.
• Focus Ground Units Second: Durable melee walkers and burrowers take longer to eliminate. Clear the mobile aerial units first, then focus continuous fire onto the ground forces before they reach the dome base.
• Extract the Relic via the Central Shaft: Once you breach the lower biomes and discover the primary relic, haul it straight up your central vertical shaft. Dock the relic into the dome foundation and activate it immediately while keeping shields stable to finish the assignment.