Alright I’ve been thinking about the spirit world stuff and this is something I think would be interesting.

During normal gameplay you control Youmu like you would Link and her ghost half floats around her like it should. The press of a button switches things however, and makes the “spiritual plane” visible or something like that. At this point you can only control Youmu’s ghost half while her human self stands in place.

There are hidden items and other stuff that are only accessible in this mode. The ghost half can not move very far from the human half but it can access areas Youmu wouldn’t be able to reach on her own like small ledges (but this has limits).

Enemies can also be interacted with differently in this mode, although they still move and behave normally. There may be enemies who can only be defeated in the spirit world and others who are the opposite. Enemies who change form when you switch modes can also exist.

The ghost half can’t be normally hurt except by specific things. The human half can still get hurt in this mode so you have to be careful about activating it.