Rambo was banned in Myanmar (formally Burma), and bootlegs are a hot item. Burmese Freedom Fighters have even adopted dialogue from the movie as battle cries, most notably "Live for nothing, or die for something." Sylvester Stallone said "That, to me, is one of the proudest moments I've ever had in film."
Sylvester Stallone specifically wanted the film to be set in the midst of the most brutal ongoing global conflict that was basically ignored by the public and media. After ruling out established (and well-known) conflicts in the Middle East, Latin America and Africa, Stallone talked to international experts who told him about the Burmese junta's mass murder of the Karen people. He then set the movie's storyline in the middle of this genocide.
Many critics and audience members felt that the horrific wounds inflicted by the M2 .50-cal. heavy machine gun in the finale were so gory that it was unrealistic. However, returning Iraq and Afghanistan veterans who had used the M2 in combat noted that the wounds were quite accurate, and if anything, toned down from reality. In the audio commentary on the DVD and Blu-ray versions, Sylvester Stallone himself makes note of this fact.
Originally, in the final battle, Rambo was supposed to hold the M2 .50-cal. machine gun in his hands and fire it, but when fully assembled the weapon weighed 120 pounds. Sylvester Stallone was still capable of holding and firing it, but it was too cumbersome for quick movements, so it was mounted on the back of a Jeep instead.
Maung Maung Khin, who played the Burmese dictator Tint, fought for the Karen Rebels in real life. He was afraid his family would be murdered if he took this role, but he took it anyway.