A Middle-Aged Man Who Returns from Another World Goes Back to When He Was 17 and Becomes Unbeatable

He thought he was going to return to his original world as an ordinary working adult, but instead he found himself back in the world as a 17-year-old high school student. He was going to enjoy the 90's with ease, but when he learned of the existence of the “human-eating variant” through his childhood friend Yui, Kazu throws himself into battle in this world as well, using his otherworldly cheats as a weapon.