The author's theme seems to be thinking, "if you take a mundane medieval world and throw in monsters and levels, how would society realistically develop?" And his answer is, "A tiny few will use their wealth and/or political standing to monopolize experience and equipment, solidify their rule...
1) In the raw, it's just ストーン, with no exclamation point. すとん / ストン is a 擬音 (Japanese mimetic phrase, something like a "sound effect") meaning "to fall/hang down". TL was apparently confused, since ストーン does indeed sound like a transliteration of "stone" into JP.
tl;dr it's just the sfx for...
With respect to the ストーン on page 9, rather than "stone", I think it's means to be an extended ストン, a manga 'sound effect' for something sinking or hanging straight downward (in this case, the demidragon he's kidnapping via a mist gate underfoot).
So... all she says is, そういうの嫌い "I hate this kind of thing". Dino-Takafumi is depressed because it's tantamount to saying, "I hate you" in JP. Fujimiya is pleased with how much this upsets him because it essentially confirms that he does like her back.
I get that cultural differences mean some...
Tein, huh? I wonder what the author's going for. It's just hiragana in the raw, and the sound doesn't map onto any word phrases off the top of my head. I guess if you impose a Japanese reading on the Chinese word for mudra (手印), you could get that (手 and 印 as individual words are read "te" an...
No worries, I wasn't doubting the translation, just that the author properly thought that through.
In chapter 2 we see him commenting on ¥400 for a 500ml bottle of water as "tourist attraction prices". Actual conbini water prices seem to be about 100-400円, so the currency itself is probably...
True, there are too many unknowns to say it's inefficient.
It's definitely not even close to competitive with non-fictional aircraft, though, and it seems bizarre to me that they live in a world otherwise indistinguishable from modern Japan, yet lack said aircraft. Or that they have both...
Ticket cost is nowhere near operating cost. Airfare is not a for-cost charity.
For example, a fully loaded 747 costs about $6,240 / hr in fuel. A mid-haul flight is around five hours (most flights are shorter, but I'm trying to use figures most generous to your case). At a conservative...