I haven't seen the movie yet, but am familiar with the Hugh Glass story. The parts of the story that seem fake (attacked by bear, left for dead with no gun, tools, etc, crawling for miles, finding a buffalo kill) are actually the real deal. The real life ending was pretty anticlimactic, and i'm guessing this is where hollywood took over, but the "survival" portion of the story is true.
And congrats to Eric, great to see real and accurate representations of bows and arrows in a film.