I can't understand how this piece doesn't have a higher score.
MAJOR SPOILERS!
Imo I don't see this game as having a "message" per se. I see it as story about morality and humanity. In the beginning we see a wounded animal being put out of it's misery, but in a sense it ends with another wounded, broken creature being out of it's misery. The blond kid having been so distraught from not being able to break the window glass in the car accident now lives on with the guilt of his mothers death. Punching being his only means of trying to break the glass is the reason he has now taken upon using his fists to assert power.
The wolf and bear bosses to me were more symbolic then they were literal, the kid's becoming even more powerful predators then any other animal in the woods. The final fight after the blond kid kills the forest ranger is the player character's sign that he has to now break the cycle. The last "animal" that need's to be taken out is his mentally wounded, unstable best friend.
When the player character get's back to the body to explain everything to the police, the animals in the forest have already done away with the body. either as a sign of pure benevolence or even as a way to hide the evidence of what had taken place so that the player character would not be punished.