Edit: apparently this is a very common form of Japanese storytelling called an isekai. There are 8 billion people in this world, no idea can be original. And sometimes you miss out on things many other people know. I’m clearly one of today’s lucky 10000.
I would be shocked for sure but how would I know how to react if I don’t know what this new world is like? Does it look like a barren wasteland? Does it look like Dinotopia? Does it look like a different planet altogether? When you say ‘unknown’, is it unknown to me only or do you mean it’s completely devoid of any civilized/intelligent species?
It is exactly like our world, only all doors that you expect to open outwards, actually open inwards, and vice versa.
Then I won’t even notice I’ve world swapped until I meet my clone
Motha getting isekai might be worth a watch.