Spherechild
Spherechild is a Pen&Paper-RPG in which adventures take place on multiple worlds (for example Fantasy and Sci-Fi). But instead of taking one character to multiple worlds, every player has a character for each world and switches between those.
Each of the worlds (spheres) has a unique feature like magic on the Fantasy sphere or High-tech on the Sci-Fi sphere. You can’t travel from one sphere to another, but the bad guys can. They use each world’s unique features to create chaos in an attempt to destroy the spheres.
You are a Spherechild, a chosen one with numerous special powers. You have to use your telepathic connection to your partner on another sphere, in order to support each other in fighting the bad guys and restoring balance between the spheres.