I'm not gonna give off many specific details in case this spoiler still kind of matters, but I found out the use of the Bone Key accidentally in Dungeon 8, and I love the huge nostalgia trip to LTTP! This felt even more amazing since I found it by mistake, and I love what you guys did for the journey to the upgrade.
Looks like I'm part of the lucky few in "the know". Yeah, I liked that part, too. The dungeon was quite different than the others to, with some unexpected puzzles. Cool thing.
Ironically, I have found the area MUCH earlier than I was supposed to because of lack of tools. Heh.