You just came up with a good name for this type of interface: the Easter Egg Interface in which everything need to be discovered, a bit like walking through a forest with paths to the South, South-East and North and there is an old house there with a mailbox, the flag on the mailbox is raised.
That just sounds like an interface without enough affordances to be understandable to the user.
Reminds me of Snapchat (at least when I used it a couple years back) - to block a user just tap and hold their name, then swipe right twice, then turn your phone upside down.
