Rickson Gracie was undefeated with over 400 wins while he entered the tournament in the documentary film 
Rickson was very determined. His mission was to spread Brazilian Jiu Jitsu as an art form to the whole entire world!
Yes and it worked, every MMA fighter learned BJJ to this day it is a very important martial art to learn if you want to be a MMA fighter
Rickson Gracie actually featured in the 2008 movie "Incredible Hulk" as the martial arts instructor. 
O yeah i forgot about that, he is a superstar in Japan 
Choke really is a great documentary about martial arts.
Yes i agree ! i have watched it about 20 times it is a must see for MMA fans especially BJJ fans and practitioner's 
Have you seen any more martial arts documentaries worth mentioning?
Yes there is one about a fighter called Mark kerr the machine
I've never heard of that one. Is it also about Gracie?