I think an interesting dungeon mechanic would be to have doors that only open when a specific item is placed on a specific pedastel. Working like a more in depth large key i suppose. Being able to set doors to need 1 or more colours would be cool if this gets added. Say you need to search a dungeon for both a red and blue skull, or just multiple blue skulls or something like that.
The mechanic being very similar to ULTRAKILLs skull key system, where you need specific skulls to open certain doors.