I have clocked 44 hours in Stardew Valley so far. I can honestly say it has been eating up a lot of my free time. (Sorry for the lack of updates!) Fun game, very enjoyable, priced right. As for the secret, not sure what it is, but I do follow the folks on the reddit @
https://www.reddit.com/r/StardewValley/ and some users there have also been on the hunt. Also a great place for information and resources, and the game developer even posts and replies there sometimes.