Waldo took out the materials for upgrading the advanced underground fortress. He clicked on the system assistant and initiated the upgrade process.
"Respected survivor, do you wish to upgrade the advanced underground fortress?" the system prompted.
Waldo clicked the "Yes" button.
The system window displayed the required materials for upgrading the advanced underground fortress:
Energy Stone: (1/1)
S-Alloy: (138/50)
Concrete: (2892/2000)
Waldo input the necessary materials, and the underground fortress underwent changes once again.
Firstly, the area of the underground fortress expanded once more. This time, it extended beyond the boundaries of the villa, at least expanding by one circle.
But what surprised Waldo the most was its depth. The advanced underground fortress had now opened up a second level! This meant that there were more rooms, storage, and other facilities to enjoy.
Ding!
