How it works
Survive factory expansion without allowing pollution-driven attacks to disable production. Each stage in the walkthrough below has a distinct practical objective; complete the current supply or control loop before expanding it.
Practical advice
Use overlays to see pollution reaching the surrounding environment and enemy nests. Increased mining and coal usage can increase pressure over time.
Mistakes to avoid
Never assume an unrelated blueprint or another version of Factorio has identical recipes, technology unlocks or machine ratios. Use the checkpoints in this guide to diagnose your own save.
Defense, pollution and enemy evolution: complete walkthrough
Inspect the threat map
Use overlays to see pollution reaching the surrounding environment and enemy nests. Increased mining and coal usage can increase pressure over time.
Prioritize vulnerable sites
Power plants, ammunition output, rail junctions and distant mines can be high-value enemy targets. Protect them before adding nonessential machines.
Build sustainable ammunition
A turret is only as useful as its ammunition or electric supply. Use belts, storage and monitoring to maintain defense while busy elsewhere.
Upgrade intelligently
Improve military science, damage research and defenses as enemies become stronger. Combine walls, guns, lasers, flame or artillery based on available infrastructure.
Revisit the perimeter
Expansion of territory and pollution changes the useful defensive perimeter. After every major outpost, verify supply routes and enemy approaches again.