Compared to the sky blue of the Deep-sea Shelter, the faint green of the main shelter's interface was always so gratifying. Moreover, it symbolized nature, life, and hope as well.

Seeing the new features expanded after the shelter level was upgraded to lv2, Su Mo nodded in satisfaction. At the same time, he tapped on the small question mark that appeared behind the level banner, selecting it in his mind.

This question mark did not appear during the last upgrade, but only did during this upgrade.

[Underground Refuge Lv3 Upgrade Preview]

[Condition 1: The main shelter should have already survived at least three disasters and, when the disaster ends, the durability of the shelter cannot be less than 50%. (Automatically entering the position of top ten in the world +1)]

[Condition 2: The overall area of ​​the main shelter should be more than 200 square meters, and should have a complete living support system (bedroom, kitchen, bathroom...)]

[Condition 3: For underground shelters, the above-ground buildings must reach lv2, and the underground buildings must also reach lv2]

[Condition 4: For above-ground shelters, the underground buildings must reach lv2, and the above-ground buildings must also reach lv2]

[Condition 5: Pay 1000 disaster points to upgrade]

[New feature preview: Sanctuary (within a 3-kilometer radius of the main shelter, when a person that owns a core enters the territory, under the condition that the core level of said person is not higher than the main shelter's level, he/she will be regarded as one. Disaster level will not be increased. Quota of people: 5)]

[New feature preview: Submerge (the shelter submerges five meters deeper underground. Number of uses: 1)]

"Hey, it takes so many conditions to get to level 3, especially condition 3. Isn't this a restriction specifically aimed at pure underground shelters?"

The new feature regarding the sanctuary that would be provided upon reaching level 3 was not very practical for Su Mo.

On the other hand, to submerge five meters deeper, this new feature piqued Su Mo's interest very much.

In addition to the current five meters, the shelter would be able to submerge a total of ten meters. With the help of the thick stone walls, even if an atomic bomb were to strike, as long as it was not dead center, Su Mo would not have to be worried about the shelter when he was underground, where only shockwaves would be felt.

"It is a must to upgrade to level 3, but it has to be planned carefully. 1000 disaster points are required. That requirement alone is extremely tricky!"

Pondering the conditions stated, Su Mo tried to understand the meaning of these functions.

First was the new function of the shelter that allowed the base to accommodate five strong players of the same rank.

At the same time, this function also made it clear that one could be added to the shelter without needing anyone to leave marks, avoiding the awkwardness between groups of stronger individuals.

As for the above-ground and underground buildings reaching the second level, stated in conditions three and four, it showed that the game panel wanted to influence the direction of development of everyone's shelters.

"The second-level's ability is connecting, which ensures that the above-ground and underground can develop simultaneously, paving the way for reaching conditions 3 and 4 to achieve level 3. One of the third level's abilities is providing sanctuary. These conditions were made to expand the number of people in the shelter. If this trend continues, would the fourth level encourage rallying around and uniting everyone as one?"

"No! Although Magoo raised his shelter to level five, he chose to be alone from beginning to end, so... how is his shelter level five?"

Looking at conditions 3 and 4, Su Mo suddenly thought of Magoo's upgrade route.

Magoo's shelter could be seen through the attribute interface as an underground shelter, but his Deep-sea Shelter has no above-ground buildings at all, even the second floor for entering and exiting was also inside the hill, which was regarded as an underground building as well.

Since Magoo was able to reach the fifth level, it proved that he had completed the third level and, incidentally, also passed the subsequent fourth level.

Su Mo tried to check the attribute panel but, unfortunately, the levels of the attached shelter were locked and Su Mo could not see the following upgrade conditions.

He tapped on the interface and found the description of the Deep-sea Shelter. Looking at the text displayed, Su Mo began to carefully analyze how Magoo avoided the strict requirements of the system and reached the upgrade conditions.

"Magoo's shelter was inside a hill, while mine is also inside a hill!"

"The first floor of my shelter is five meters underground, his shelter..."

"Huh?? Magoo manipulated a bug!"

With a flash of inspiration, a detail jumped into Su Mo's mind.

Judging from the description of the Deep-sea Shelter, the Deep-sea Shelter must have been built from the bottom up. This could also be seen from the layout of the first and second floors.

All the valuables were placed on the upper floor by Magoo, and the lower floor had been turned into a garage.

Strictly speaking, although the Deep-sea Shelter was an underground shelter, in Su Mo's opinion, it was not much different from an above-ground shelter.

Especially when entering the second floor, one would need to walk up the hill to enter.

This led to the fact that, in the judgment of the game panel, the top floor was deemed an above-ground building, and the lower floor was considered an underground building.

Using the connecting function of lv2, Magoo easily connected the upper and lower floors and took control of both the floors simultaneously.

"Smart! Magoo is really smart! Sure enough, when one survived up to the last 1%, one had to have something up their sleeves!"

Slapping his forehead after understanding the upgrade bug, Su Mo's mind came alive.

If he was without Magoo's guidance and wanted to achieve a lv2 level above-ground building, Su Mo would still be thinking about building one on the ground.

However, a brighter road had appeared!

Since Magoo did this and the system recognized it, that meant that there was no need to build the above-ground building.

He only needed to ensure that his buildings were, to some degree, above the ground!

"Three floors! I know how to build additional layers more efficiently now! Magoo did not build the floors from top to bottom, but from bottom to top!"

The current shelter only had one floor, and it was submerged five meters deep underground, which left enough space above it!

As long as a layer could be built on top of the shelter, the two would be superimposed and, through the connecting function, that layer would become the second layer.

Then, when the time came, the shelter could be upgraded and submerged again to build another floor above it, and the one standing above would become the third floor!

"It turned out to be built according to the principle of stacking bricks. It only needs to be stacked one by one. If there is enough depth and sufficient cores to submerge even deeper in the ground, even dozens of floors underground would not be a problem, let alone three or five floors."

"It seems that I had been misguided in my way of thinking before. I always thought about how to continue digging a hole five meters deep underground. It seems that I still don't understand the gameplay!"

Although his words sounded angry, Su Mo's face was filled with joy as he tried to figure out how to play the game.

According to the current submerging range of the shelter, as long as it could rise to level 3 and submerge again, the shelter could instantly become a four-story building after adding in Magoo's number of floors.

In addition to the above-ground buildings, it could even be counted as a five-story building.

Safehouse cores would be needed on each floor to expand them to 220 cubic meters, that would be five floors of 220 cubic meters which, when added up, totaled ​​thousands of cubic meters of available space.

Not including the additional cold storage facility and other buildings.

As long as there is enough food, given such a large space, it would not be a problem to support a team of 100 people in an instant!

"Of course, some buffer space should be reserved above, for example... a garage can be built on the first floor!"

"Although the current hill is not large enough, I can expand it. As long as I get enough soil and add that in, it can be made into an air-raid shelter hill, reinforced with iron bars and concrete added into the structure. It would be camouflaged and practical!"

The huge and crazy upgrade plan came out of Su Mo's mind, and the accompanying inspiration also spewed out generously.

Although he was not an entry-level architect, nor had he undergone professional studies, for half an hour, Su Mo sketched out a simple prototype with a pen and paper on the table based on his whimsical ideas.

The first objective was to create a free-standing structure on the ground above the underground shelter, using a complete safehouse core and the principle of stacking bricks to stack a layer above the Underground Shelter.

At that time, the newly-appeared layer could be directly connected to the top, becoming the second layer.

Then the shelter would have two floors. The distance between the first floor and the ground would be exactly 0.8 meters deep.

After that, reparation of the second floor of the Deep-sea Shelter to become the garage of the Underground Shelter.

4.8 meters high, minus 0.8 meters after submerging, it would equal to exactly four meters. Hidden inside a ten-meter high hill, it could ensure safety and also easy access!

Moreover, such a height meant that it could be included as part of the Underground Shelter, using the connecting function to ensure an integrated defense design.

The garage could become an above-ground building that satisfied the lv3 upgrade requirement!

"As long as I pass sufficient disasters, and have enough disaster points, I can immediately upgrade the base to lv3, and aim for lv4!"

"It turns out that the greatest benefit of Magoo's shelter was not the transcendent blessings or reparation, but his diary and this advanced information!"

"With these, I can figure out the road ahead and come up with the best solutions!"

Su Mo took a long sigh of relief and looked at his designs for the shelter. While the designs were a bit disorderly, they were labeled neatly. Su Mo was in an eager mood and wished to upgrade it straight away!

"No hurry, I should pack my things and go out now. First, build a 220-square-meter floor above the Underground Shelter, and then pack all the good things in the Deep-sea Shelter on the second floor, before sacrificing it over!"

Calling out to Oreo, who was still resting, Su Mo stood at the door and began to put on his equipment.

Being able to farm wildly, and having enough resources to transform the base without the interruption of enemies, the joy was more than ten times, or perhaps even a hundred times, greater than playing those sandbox games on Earth!