I took the two keys but I still don't know what the second key is for and how to unlock the explicit scenes, not to mention the chest in the labyrinth that cannot be opened?
The sex scenes are exclusive to the Unify route. After the plant matching mini game, Billy will mention the graves, so after that cutscene you'll be able to dig up the grave with the tall dead grass stalks (or wheat, probably looks more like wheat). The second key will unlock the chest that was buried there, which gives you a third key that you can use to unlock the locked chest in the hedge maze. This'll give you the deed to the farm, and will change the escape cutscene.
