Mines and Warehouses
The extraction of resources is key to play and this is possible thanks to the mines. When you upgrade mines, they extract more resources faster. The higher your current level, the more expensive and slower your upgrade will be. For each type of resource (Metal, Crystal, Petrol) you will have the following mines:
Once the mines extract resources from your planets, they are stored in the corresponding warehouses. The higher the level of your warehouses, the more resources you can store in them. When you have a full warehouse, the production of that resource will continue, but the resources produced will be lost.