So I'm completing the desert palace, have the boss key, as well as one more small key. I'm in the long vertical narrow room to the left of the room with the boss key, but the door to the left is not open. It has one of those mask/faces on it.
I have been all over the dungeon, and this appears to be the only door I cannot pass through. I have not been able to get it to open. I'm almost wondering at this point if it's a bug!
Anyone know how to open the door, or know where I should try going?
I'm also going to try and update with screenshot.