Thanks. I wanted to try an embody the feel of levels growing progressively more challenging like the old video games. I also included hidden methods of "warping" the party forward in the adventure like so many NES games had.
In games like Gyromite you need to solve the puzzle before time runs out or you die. So that inspired the idea of using the real-time constraints, which I thought paired nicely with the Shadowdark torch timer mechanics.
I figured the adventure was brutal enough as is, so I added the spirit encounters as a possible result that could give clues or luck to aid the party.