Your Girlfriend Was Amazing - Chapter 27: Thank You For Trusting Me

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.

Fang Heng was transmigrated to a parallel world and his soul was forced into the body of a man who had just committed suicide.Huh? What? Every human here was being forced to join a game? Those who refused would be killed?Wait? This suicide dude was a pro gamer?He had the highest S-rank talent sill, the Zombie Clone?Damn! The S-rank skill evolved! My zombie clones could auto hunt![Your zombie army has crafted Wooden Axe x720 when you were offline. You have received 1921 experience points for the Basic Crafting skill.][Your zombie army has chopped down 27,821 trees and gathered 128,973 pieces of wood while you were offline. You have received 2,171,921 experience points for the Basic Wood Chopping skill.]Just as the rest of the players were struggling to survive in the zombie apocalyptic game, Fang Heng's zombie clones were starting to clear every resource out of the forest.Hm... What an interesting game!

Harry got a strange Life Achievement System which assigns missions that reward him for acting like a scumbag and earning Scum Points.Scum Points Could can be exchanged for powerful magical items, rare abilities, and tools that give Harry an edge in both life and business.At first, he resents it. Then he gets curious. And finally… he gets hooked.But being a scumbag is a high-risk profession. One wrong move, and he could lose everything, even his life. To survive this dangerous game, Harry must walk the line between manipulation and strategy, charm and ruthlessness.He’ll cheat, scheme, and hustle his way to the top.

This is a prequel to the anime movie To Aru Majutsu no Kinsho Mokuroku – Endymion no Kiseki.

Just before the completion of the Academy City space elevator “Endymion”, the main characters Kamijou Touma and Index encounter a level 0 girl named Arisa. The Magicians are after Arisa, and they attack Academy City. A female leader named Shattoaura leads a unit from Academy City against the attack. Kamijou and Index learn from Stiyl that Arisa is key to a brewing war between the sides of Magic and Science. When science and magic cross paths, the story begins with Endymion as its stage!