I'm a Doomsday Engineer, and the Nation Came Looking for Me from the Start

Reborn one year before the apocalypse, Su Chen binds himself to the [Black Technology Livestream System]!

By livestreaming inventions far ahead of their time and collecting viewers' astonishment, he can exchange it for terrifying technology powerful enough to withstand the apocalypse!

[Hand-assembles an electromagnetic hand cannon that punches straight through a steel plate. The entire internet erupts, and the Public Security Bureau shows up at his door on the spot!]

[When questioned by a policewoman, he explains the "Gauss coil accelerator" on the spot and calls the weapon of mass destruction a "teaching aid," leaving her speechless!]

[Writes down a formula on a whim, solves a technical bottleneck for a trillion-yuan conglomerate, and receives a million-yuan payment instantly, all so he can rent a bigger workshop!]

[...]