I was surprised by my not being more confused by the movie, because time travel stories do tend to fry my brain. But one thing I'm not sure I got was why there were two scenes of the Old Joe/Young Joe shooting, one where he gets away, Young Joe flees to his apartment, then falls off the fire escape. That then cuts to him in the field again, shooting Old Joe, and then flash forwarding to his future. What?

See? my brain just fried.