If you've done the installation as shown at codespells, you can preview this world now by using:

(once-upon-a-time
  #:world (cave-world)
  #:aether (demo-aether))

Starting next week, I think I'm ready to start releasing builds of these worlds -- so you don't have to go through the installation process with Racket first. I think I can get the compiled Racket executable and the compiled Unreal executable to be zipped up in one nice folder for easy installation.

- Stephen R. Foster