No unlocks or anything to report, but some of the revelations of the people we've put to the question have been... enlightening (sorry, couldn't help myself there).:
- Not just the front of advisor cards, but the backs also sometimes have hidden messages
- We got told the "map" has messages as well... checked all over, best we can tell so far is that the tombs map has some odd symbols on it that we can't decipher.
- Tablets also apparently have something on them, but we found that out right at the end of the game, so no knowing what all's involved there.