Gimai Seikatsu - Days With My Step Sister - Chapter 64 - 12

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.

He is the master of six kingdoms. As long as he wanted, his cavalry is ready to wipe off any country.

Looking at the desperate survivor surrounded by zombies under the high wall, Tang Ye opened his hands and shouted: Welcome to paradise (Welcome to heaven)

- Description from novelbuddy

[After choosing to farm, I turned the cannon fodder female partner into a winner in life]

With the life support system, Xu Yin penetrated into the world of thousands of novels that she had complained about, and all of them ended miserably, and were the best cannon fodder for the heroine to serve as the control group in the beginning.

Xu·Fo’s small farming expert·Yin: …Hold on! It’s okay to lie down with salted fish, just don’t get involved in the plot!

Hang on, and become a winner in life.

Small world ① 80 best sister-in-law: stay away from the best, farm and make a fortune;

Small World ② Select and farm as an elite female matchmaker: If you are an elite, you can farm to strengthen the country;

Small World ③ The oil bottle of reorganizing the family: Goodbye step-sister! Return to your hometown to farm!

Small World ④ World Champion’s Ex-Girlfriend~

Small World ⑤ The control group of the Almighty Actress~

…

More small worlds are being produced…

- Description from novelbuddy