I wasn't really planning on playing the game through a second time. However, when I loaded up the scene to check out the quotes ingame for this answer, I noticed that I was getting different narration than previously.
Does anything else change in the game, like the environment, items you come across, or scenes?
Throughout the game there are trigger points that are in fixed positions.
Each trigger point chooses an item from a set of narration parts that are available for that specific location. So on my second playthrough I had mostly different parts of the monologue and some that were the same as the first one.
Furthermore I noticed that on the mud bank, in the cave near the blue river, I noticed the second time through there was not only a polaroid, but also a bird's nest.
Not certain if I just didn't notice it the first time or if it was an actual difference.
It's completely randomized. Sometimes there is a wedding ring on the ledge in the last house before the tower. Sometimes you see a figure standing on the path ahead, always in a position where you must lose line of sight to reach it, only to find it deserted upon arrival.
