Here's a bit of a thing. I happened to look at my "game design" folder, which is of course full of random snippets of text dating back years. The oldest file is from 2003:
Research: enter a book "room", use standard IF search techniques to explores, find "exits" to other pages or other books. Books can be hidden in "real life", or just not indexed in the library. Similarly, a section of a book might not be findable until you find a reference elsewhere, and search for it.
(Library is a real-life room; the books you're familiar with are pulled out, handy. Reading one enters the book "room".)
Alchemical operations form a deep skill tree. As you perform operations successfully, they're added as single action. ("distill alcohol", "resublimate thiotimoline"). Lots of room to explore. Operations have logic, but also exceptions.
Time limit? If you screw up, or take too long, your supplies and tools are restored to their original state -- new day begins -- but you retain your skills. Maybe even get pre-made supplies of stuff you're very familiar with.
Operations take particular amounts of time? So there's an optimization problem, even for skills you've learned. (Ameliorated by pre-made supplies.)
No idea what the story looks like. Something about the reason why you are taking this alchemical test and have an infinite number of retries.
That's all I wrote back then. It's old enough to have MacOS-Classic line breaks instead of Unix/OSX line breaks.
When I started planning HL in mid-2010 I started a new notes file, but I left the old one in place. Obviously some of that old stuff went out the window. Although now I like the idea of books as environments which you "enter" to do research. Maybe I'll try that again someday.
For more fun, here's a snippet from the 2010 notes file:
Planetary types: (A marcher doesn't normally visit these, but they're familiar from the academy and from sailor's stories. The protagonist has never seen one before; he's only visited Gaian lands, and rarely left the Retort except in inhabited places.)
- Gaian lands: where people can live.
- Hadean lands: rock, little or no air, "night" sky. (The Moon, Mars.)
- Helian lands: like Hadean lands, but with a big honking sun. (Mercury.)
- Erebian lands: like Hadean lands, but covered in ice and with little sun. (Pluto, etc.)
- Thalassan lands: oceans (of something) and atmosphere. (Titan, probably.)
- Aeolian lands: only clouds visible. (Jupiter, but also Venus.)
- Hermetic lands would be fairyland or Atlantis. Places populated by the Wise. The term is from popular fiction rather than science.
All of that is canon, but it's only briefly referred to in the released game.
I'm holding onto the hermeticlands.com domain as a placeholder. For what, I don't know yet.