Doomsday Simulator: This is not a game

An inexplicable simulated world gaming headset allowed Song Han to enter a doomsday zombie world that was exactly the same as the real world!
[You have been killed by zombies, please restart the game! ]
...
[Congratulations on killing 70 zombies! You received the attribute reward [Zombie Killer ③]: Increases your attack damage to zombies by [-]%!]
Congratulations on completing the construction of the Doomsday Fortress. You've received the attribute bonus [Ironclad Fortress ③]: 100% protection against damage from natural and unnatural disasters!
Congratulations! Your safe zone's output has reached a certain level, earning you the attribute bonus [Abundant Food and Clothing ③]: Increase resource output within your safe zone by 100%!
...
[Alchemical machine + saltpeter = black powder! ]
[Alchemy Machine + Science Machine + Steel = Automatic Drilling Machine! ]
[Alchemy Machine + Science Machine + Intelligent Machine + Heavy Machine Gun + Reinforced Concrete = Unmanned Heavy Machine Gun Bunker! ]
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Under the red moon, Song Han, who regarded this world as a pure game simulation world, happily built his own safe zone fortress and doomsday happy house, and enjoyed the fun of hunting zombies to his heart's content!
Until one day, the moonlight in the real world was tinged with a crimson glow, and the doomsday zombie world began to overlap with the real world as if it were a parallel time and space!
At this moment, Song Han suddenly realized: This is not a game!

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