It would be awesome if there were secret levers.
There should be a secret torch lever and/or bookshelf door/lever
The torch lever would look a little different so if you look closely you can tell its a lever.
it would be crafted like this:
The book shelf could either be a hidden door or a lever. Maybe if you clicked a special book then it opened? dunno if thats a good idea. but it would be cool.
the book shelf door would be made like this:
  
  
the book shelf lever would be made like this:
  
  
These dont have to be how they are made cause if you have any ideas I'd be happy to hear them.