From the announcement:
A Riddle is found in this teaser of decrypto (Exit 2018). SOLVE IT TO WIN 2 copies of the game before its release. Share massively, ask for help in "tagging" your friends, gather around, because it's big!
#Decrypto is a communication game in which you join a team of encrypteurs. Your Mission is to transmit secret codes to your teammates without your opponents being able to intercept them.