Who is the enemy???

After finishing Platoon, it became fairly obvious that the enemy was uncertain. The Viet Cong was never seen, but only in shadows. The enemy was portrayed as invisible and everywhere. Pvt. Taylor summed it all up at the end when he said: "We did not fight the enemy. We fought ourselves. And the enemy was in us."
Taylor, the main character, began with an idealistic view of the war at the begining, but the raw experiences of that war unfolded the reality of the truth: Good vs Evil. That battle took place within every soldier. By the end of the movie, Taylor was no longer the same.