Loser System and Berserker Me - Chapter 133: Night of Unease

Bound together by an imperial arranged marriage, Li Yuyan is scorned for her association with the ill and blind crown prince. Publicly, she stands up for the seemingly gentle and perfect prince, and he in turn protects her from criticism. Privately, she contemplates inheriting a fortune if he dies, while he considers eliminating her if she steps out of line. Unknown to all, the beauty and brilliance they keep hidden will unveil. During their wedding night, as she cures his blindness and cold ailment, but not his secret illness, she discovers the deceit. Realizing she's been tricked, she tries to flee, only to find herself trapped by him as he expresses his fascination with her.

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.

1. Download a suspicious game
2. Catch a few magical pets as partners
3. Go through interesting daily routines and lead the pet shop to a whole new level

- Description from Novelupdates