Video Game Tycoon in Tokyo - Chapter 1003: Dominant Position

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.

Set on a giant, almost finished bridge between Sadogashima and Niigata. Abandoned by the government, the bridge, and the giant man-made floating island at the center, has become a city of criminals and societal drop-outs.

Set in the same world as Durarara, but 15-20 years later. There is almost no overlap between Etsusa Bridge and the other novels.

Su Yu, who was idly passing his days in a third-tier university, ended up in a terrifying unknown forest due to the “Sinkhole” incident. His school collapsed into the “sinkhole”. The forest was filled with various terrifying mutations, which started, right in his hands.

Lu Xiao had followed his master for eighteen years, excelling in both medicine and martial arts.After five years of military service, he returned to the city to search for his origins.Faced with flashes of knives and shadows of swords, he was decisive in killing, dominating everyone.When it came to the matters of the heart, he said, “Still… the Young Miss is the best.”