Page 5: From that background I would say you are in Aincrad.
If magic is part of the natural world it is science...
"The world is not ruled by science but this cheat lets you by pass a scientific law"...
The world building is so bad it is comical, the MC personality saves it all though.
The guy is a Planeswalker now! Coolio!
What a dumbass...And I'm not talking about the fact he turned down the cheat skill. Not alone. Instead of firstly taking that girl out of danger, before attempting to take down the truck, he bet her life on his own success. As he said himself: He did step in, because it was the perfect opportunity to show of. Well, wasn't that perfect, right? (My bad. Remembered it the wrong way. Yet still, this opportunity to experience this face-off was more important to him, than to make sure the girl lives.) And in the end, it was a truck!
And then there are the cheat skills he turned down: There are so many different kinds to pick, that help in normal life and don't interfere with his battle prowess. How about higher sympathy states, when he meets people? He does dearly need it. Or an outer-dimensional subspace dojo, he can visit whenever he likes? A simple item box? Three free meals a day? Access to rice and soy-sauce? A self-regenerating karategi? He didn't want any, so he also shouldn't be able to understand those people. (No auto-translation cheat skill.)
Also that dumbf*ck is lucky AF, to be left alone in battle with the minotaur. Seemingly that bad-guy is MC's intellectual equal. I would have launched an inescapable attack at him at the worst moment for him, no matter how small, like magic-missle, an instant magical power beam (instant, because it travels with light speed and hits him seemingly instantaneous), a smokescreen around his head. Anything to interfere.
MC is so arrogant regarding his skills, it already literally killed him once. But I hope this might become a second putin-isekai...there is a small ray of hope.
EDIT: Regarding later chapters and that small ray of hope...
In later chapters he isn't a total moron anymore. Most of the times he actually acts rather cunning. The manga becomes a lot more enjoyable.
@bewoulf Same, this shit kinda of just appeared randomly, honestly at this point they are making Isekais out of everything...
@Qelix My nigga what is that essay, you can't possibly be that hipsterish, you do realize the literal title of the manga is "Idiot Karateka in Another World" xD...