Everything you see is actual gameplay from Mount and Blade: Warband multiplayer. The entire trailer was filmed, edited, and uploaded in less than 12 hours. Starting with an idea inspired by the soundtrack, my friends helped me film the scenes one evening.
Warband is one of the funnest games I have played. I like to think of it as a FPGS, or First Person Glory Simulator. There are plenty of shooter games and even magic casting RPG games, but when it comes to delivering gritty medieval death and honor, Warband is the game for you.