hidden key?

[Top Fuel]

I solved the globe puzzle, and got the hidden key. I can not find where to use the hidden key though. Does anybody know where to use this key, or is it fake? There is a door that says requires a special key, but it still won't open?

[Alexandre Fiset]

Hi! We probably should remove that key from the demo as it's used further into the game. The special door also can't be opened in the demo.

[shademoriquenda]

I have the hidden key, full game and it does not open the door that needs a special key

[Grogan]

The key from the globe puzzle is not for anything in the mansion.

It's to open a cabin, on an island you'll come across soon after getting in the boat and traveling through the transition point

There would be locked doors in the mansion in the demo, if that's the "door" the OP is talking about. The globe puzzle is pretty much the end of the demo so you won't come through those doors from the other side to unlock them etc.