On top of having a very clean, understandable presentation, this a great concept for a puzzle game! I can imagine the game introducing the mechanic with simple, direct language and slowly starting to use more obtuse language to add difficulty. Maybe adding homographs to hide important words in plain sight or make a rule that a certain type of text can't be used in a command, like any text that's being spoken.
The two minor changes that I think could be made to this version of the game are:
- When you return to the right path after pulling the lever, print the exact same text as before the lever is pulled, then add a paragraph after it, which will include the word needed to solve the puzzle.
- Give "examine" some functionality on the left path. So when the player examines the tree, a new paragraph of text can appear with either a clue for what words to look for or maybe even include one of the words that solves the puzzle.