An absolutely fantastic episode! This spiritual successor to "Underdark, Overbright" goes to great lengths to show just what Copper is about. While the difficulty and complexity of maps gradual increases throughout, nothing ever feels truly overwhelming. Quite the opposite in most cases, when you realize how cleverly connected everything tends to be. Clear indicators of what keys have been used being an obvious example. I especially enjoyed secret hunting — having found nearly all of them given the subtle shared visual clues.