Hey Eddy,
You're wrong. It's not straight-forward. ... You put tricky warps in many of the rooms! I didn't catch on until a minute ago that "sometimes, backwards is forwards"! (A clue like that would be helpful somewhere in the dungeon, but I'm glad I at least figured it out. Was that clue in another dungeon I forgot about? I forget since it's been a long time since I started the quest.) I think you meant to say that it's "straight forward and backward"!
So yeah, I found the key, but it wasn't until I started typing a response here about not finding it that I finally realized where else I could check. Go figure! Good thing I remembered to use the Lens.
Edit:
Oh, and by the way, you forgot to put Lens hints in the room right above the room with the mini-boss guarding the Master Sword. It threw me, so I backtracked and got confused.
Edited by Lightwulf, 04 January 2018 - 06:27 AM.