Oh my gooood. Talking about walking through worlds reminded me of a tool on GitHub to inject support VR into Unity games. This app only works for a few versions of Unity, hasn't been updated in a few years, and doesn't care that a game wasn't made for VR; but it's breathtaking to be standing there in the middle of a running game when it works.
Hopefully somebody can poke at the source code and find ways to expand it.