guns, fire-starters, lamps, hand-held lights, care products in plastic bottles (the care product itself is fine, the bottles ? The heck, they even have Japanese prints on them), etc etc.
In her house you have modern cuisine, TV, electricity, fridge, gaming consoles, etc, again.
This would have so much more potential if she only brought things that could pass off as foreign technology instead of blatant future tech. Things like the kitchen wares are fine but some are not, like the special coatings on some things (aluminium and other things). The craftsmen's works were a perfect idea ! They have better knowledge and experience than the people of this second world but this can pass as a foreign country which focused more on the quality of their craftsmanship, it could be the work of some master craftsman from there.
But guns ? You can't explain that, even if she doesn't sell it she doesn't even conceal it... Crossbow, YES, even a modern one is fine ! She brought both, which seems contradictory...
The fire-starter... she could've used a modern flint & steel which already produce enough sparks to start a fire but no, she had to use a handheld gas torch (or whatever it's called in English).
For the party she brought a laptop and projector... the servants used cameras to film and take pictures... HOW COME NO ONE IN THIS OTHER WORLD IS QUESTIONING THESE ? I mean, no matter how naive the servants can be, there's a limit to what you can call "foreign tech". Handheld device that can capture images of the world in real time without any apparent processing ? Just... what the fuck, this would be a godly priceless artifact in such times. The guest are all in awe because of the projector, they're even saying "what kind of magic is that ?" so far even magic doesn't seem to exist in this manga, how can they all be "oh fine, it's magic" ?! Any noble seeing such things would be all over the place trying to get its hands on such technology to boast about it or make money from it, which is entirely normal since you're putting such outrageous tech in front of them. But nope. Nothing happens aside of some cook that comes and ask for... FISH. FISH, of all fucking things this party had. FISH.
Are you making fun of us, author ? I'm in despair right now.
But yeah, if you forget about these things, plug off your brain to enjoy a silly and fun manga, this is great. Sometimes I plug it in by reflex because some things are just too much (like the laptop, projector and cameras being used in public) but other things can be overlooked easily, the manga in itself is enjoyable (but makes no sense).