Welcome to Rewind World Game - Chapter 218 - 215: "Big Brother Isn’t the Number One Player

The Special Investigations Unit is a covert organisation that no-one in the city knows about, dedicated to investigating bizarre occurrences beyond the comprehension of the living. The Chief Zhao Yunlan isn’t a simple guy either, being the inheritor of the Guardian Order, he has always been a righteous conformist, excelling between realms of the living and the dead. While investigating a school suicide case, Zhao is attracted to the calm and reserved Professor Shen Wei, but the Professor seems to be rather fickle towards him…

- Description from Novelupdates

Luo Qing Chen is a wandering spirit that died thirty thousand years ago, roaming the Chaos Space

In order to not turn into dust, she is bound by an ice cold system to travel through time and space to complete missions.

Girls that pretend to be weak?  Slap them without explaining.

A silly cannon fodder?  Helping them amass treasures.

Meeting a real male god?  All of them will pamper.

System: Dear masters, what do I do if my host even dares bully the heavens?  Waiting for an answer, it’s urgent!

A certain male god: Change systems.

System: ヽ〔?Д?〕丿

- Description from Novelupdates

Luna Lethal, a name synonymous with fear and power, ruled both the underworld and the elite circles of society. Orphaned young, she rose through treachery to become a master of manipulation and skill. Yet, her reign ended in betrayal—a laboratory explosion claimed her life. To the world, her death was a tragedy; to her enemies, a cause for celebration. But Luna awakens in the body of Aurora Smith, a neglected and ridiculed child despised by her adoptive family. Stripped of her former strength but not her will, Luna faces a choice: seek revenge for Aurora’s mistreatment or forge a new path. As her sharp mind and unyielding spirit transform Aurora’s life, shadows of Luna’s past resurface. Loyal followers sense her presence, while old enemies seek to destroy her again. Torn between vengeance and a fresh start, Luna must confront her identity. Is she still the Devil of the underworld, or can she find peace in a second chance at life?

A scientific genius named Thomas Harrier was transmigrated to an imperial prince body after a car accident that took his life. He found out that he is in a world similar to our own with a timeline akin to early twentieth century. The body that he is occupying was the imperial prince of a failing empire who suddenly rose to power after a successful assassination attempt of his father. Unaware that the attack is just the beginning of what is to come. He faces many challenges throughout. Will Thomas Harrier be able to live his second life in peace while running an empire and getting it back to its former glory? Or will he succumb into a conspiracy lurking within the country's borders?

Expect some:

Cold war era techs.

Super battleship with advanced electronics, propulsion, and fire control systems?
Helicopters?
Missiles?
Modern medicines and equipment?
AC-130?
A nuke?
Challenger or Abrams or Leopard?
F-4 Phantom or MIG-21?
Colored TV's.

Everything!!!

PS. Cover not mine, I just found it on google.