At the end of the game after Watts and Rosalene are talking by Johnny and River's graves in front of the lighthouse, the "world" begins to shake and glow red. It's the same sort of occurrence that Watts and Rosalene experience inside Johnny's "world of memories." Also, immediately experiencing the red shakies, Watts chugs some pain pills he denied being addicted to earlier.
Am I reading into it too much? Or is this alluding to the possibility of Watts and Rosalene's "real world" as being simply another "world of memories"? Were there some other clues dropped pointing towards this? Or is there a better evidenced explanation?