Amazing Engine

And that brings me on to the last point I want to talk about, which is avatars.

So, one very traditional RPG that does the same person, different universe thing is the Amazing Engine system from the 90s.

I don't think it does it very well, but it is an option.

The way it works is you have a player core and then a sort of skin of skills and magic or tech that goes over the top for interacting with any given universe.