An Kai really wants to choose two upgrade plans at the same time, but at present, the materials are still only enough for one of the plans, mainly because the number of alloys is not enough, the materials needed are too special, and the amount he can collect is really limited.

　　 So after thinking about it, Ankai decided to temporarily choose the first upgrade plan.

　　 The first upgrade plan is to increase the thickness of the protective door, enhance the ability to resist blasting, and add a metal frame on the surrounding walls to enhance the overall protection of the shelter against the enemy.

　　 Perhaps improving the concealment ability is a better choice to deal with zombies, which can prevent the shelter from being found by the zombies and the people behind them. But considering the second-mutated giant zombies, An Kai really couldn't worry about it. He always felt that something would happen in the future, so he finally decided to improve his defense first. What's more, the second-mutated giant zombies are only the current situation, and the third-mutated zombies will not be ruled out in the future, and other zombies may also have second-mutated individuals.

　　 For example, if exploding zombies also produce secondary mutations, it would be very troublesome. The explosive zombies after the first mutation can easily destroy most of the items within a radius of ten meters, and even the walls can be blown up. If it is after the second mutation, it is greatly enhanced in its special aspects like giant zombies, then The shelter at this stage is really not necessarily deceptive.

　　 Therefore, strengthening the overall defense capabilities of the shelter should be the most important thing at the moment.

　　 Choose an upgrade template, confirm and add various materials, and then the door of the shelter begins to evolve automatically.

　　 First, the original protective door was increased by about one-half of its thickness. It looked like the protective door had begun to develop again, and it became much heavier than before. Then a layer of special paint appears on the front and back of the protective door. The effect of this coating is to absorb the impact of the explosion, while having better heat insulation and resistance to expansion and contraction, which can greatly improve the protective door’s performance in special environments. Overall strength.

Then strengthen the surrounding walls. Steel bars appear on the original concrete walls. Ankai can also strengthen these concrete walls by himself, but he doesn’t have to do that at all. If that happens, the consumables will be too serious. . Fortunately, the sanctuary as a whole is underground. To be honest, it’s the end of the world. Unless there is a nuclear bomb just hitting the top of the sanctuary, or there is a special bomb designed to deal with underground facilities, ordinary attacks will not threaten at all. To the sanctuary body.

　　 So now he only needs to strengthen the protective door and defend against the enemy.

　　 Strips of steel bars appear on the wall out of thin air. They are not arranged horizontally and vertically, but laid in a m-shaped pattern to enhance the wall's defense as much as possible.

　　 The materials naturally flowed by like water, and Curry, who was in charge of guarding the passage area, looked at this scene a bit stunned.

　　Because of the cognitive distortion function brought about by the system, Curry doesn't think this scene is so exaggerated and outrageous. The reason why he is astounded is that he didn't expect the shelter to be so strengthened.

　　 In fact, if An Kai is willing and has enough materials, he can continue to strengthen. Of course, the follow-up enhancements have higher requirements for materials and skills. He is now a level 5 engineer with all his heart, and other things are not within his consideration. Judging from experience, he has two more levels to be promoted to the fifth level of engineer. Just the day before yesterday, he just filled up the wisdom master program. It is only one step away from cars, airplanes, and yachts, except for the materials. Ankai is currently Suffering from the lack of vehicle carrying capacity, now my mind is full of engineers level 5, and all other skills have to stand aside.

　　 The movement on the protective door also attracted other people.

　　 The three little guys are the most lively. Seeing the changes in the shelter, they all yelled.

　　 "Quietly..."

　　 Carter whispered at the three little guys.

　　 "Don't be like this, they are better than anything else."

　　 An Kai waved his hand again and again next to him.

　　 Before crossing, he particularly hated children.

　　 is not simply a bear child, at that time, except for the little cute baby, as long as he is a child, he hates it. Besides, I hate dogs, especially Teddy.

　　 But after crossing, after seeing the despair and brokenness of this world, the senses for children and small animals began to change. Because in such a desperate world, new life represents hope, so that a world that has become black and white can escape a touch of fresh color.

　　 So for Carter's harshness, An Kai said that it doesn't have to be so.

　　 If he was replaced by him, I am afraid that the three little guys would have been thrown out with their parents. But now, he has a good impression of the three little guys and feels that they are the pistachios of the sanctuary.

　　 "Is this reinforcement necessary?"

　　 Emma asked with some confusion.

　　 "Of course there is a necessity, and the more this is the case, the less careless it is in defense."

　　 Leo also came over, looking at the shelter that was gradually becoming stronger, with a rare smile on his face.

"Although it was the last days before, the living people can continue to live, but now, the living people don’t look like humans anymore. To survive, they can do anything. And you forgot about the time when Ann and Big Brother went out. Have you met the big guy? The second mutated zombies must be much stronger than the original zombies."

"Yes, what I am most worried about right now is the explosive zombies of the second mutation, and the zombies that we have not seen before~lightnovelpub.net~ An Kai nodded next to him, "I also talked to you in the previous situation. Having said that, I suspect that someone behind the second-mute giant zombie can directly control it, otherwise it would not be able to sneak on us so cleverly. Although it does not rule out that the zombie regained wisdom... But the possibility of someone controlling it is not small, if If this possibility really exists, can they still make zombies that can use weapons? Nowadays, normal living people can no longer move freely in the outside world, and the weapons are not powerful, but if someone can control the zombies, the zombies can move at will, or they may get powerful weapons, so the shelter’s The defense must be improved, and this is also for the safety of all of us. "

"In addition to this, there are weapons and equipment that are also increasing the range. And everyone, I hope you can continue to strengthen your shooting ability and improve your physical fitness, including Haili, and you will definitely become more and more in the future. Danger, we need stronger self-protection. Even the shelter cannot fully protect your safety. You must improve your strength."

　　 An Kai looked at everyone and said.

　　 Everyone nodded.

　　 This is also a matter of course. In such a doomsday world, it is certainly impossible to live as carefree as before. Even the trio of underage Haili sisters and brothers must continue to exercise to make themselves stronger. They don't need how powerful the ability to kill the enemy, at least they must have the ability to protect themselves, and they must not become a burden at critical moments. What's more, if anyone really wants to threaten the shelter, they must also take up arms for the future of their parents and family.

　　 This is not only An Kai's requirement of them, but also the world's requirement of them.

　　 Everyone has no opinion on this, and they are all willing to accept Ankai's arrangement.