It's a convergence of multiple worlds and universes. There are a number of copies, powerful magic and a smattering of science all at play. What they said about the portal seems to be true, and there's no way home that they know of. Lady Yukimura is investigating further, on that end.
They seem to like confiscating weaponry and offering clothing that offers little to no coverage or support. And I'm allowed to call everyone by their Christian name without receiving sighs and annoyed looks.
Science has both been driven forward and pulled back - medicines are more direct and less helpful, they rely far less on potions. Indoor plumbing is improved, as have the beds. Alcohol now comes in tiny bottles.