Continuity mistake: The main character is chasing after the guy in white. Right before he falls, the main character shoots him in the left shoulder. The mark disappears from his shirt after that.
Suggested correction: The guy was shot in his right shoulder not his left, when his head hit the rock, his left shoulder (not his right) is exposed.
Factual error: The intro takes place in March. The trees in the background say otherwise. In the mountains in March, leaves are usually not fully developed on trees until April at the earliest. The scene was likely shot in the fall.