If you read his preface on Youtube to the video, he made a setting, where the game runs at the same speed at 30fps, however, he sets the settings so the game will only keep everything at pace, so instead of the game hitting 5-15 frames per second, it slows down the player/movement to keep it in pace with the
speed of 30fps, so in a sense, it's almost like software rendering.
I guess this is how Crytek could make "ingame" videos even on older hardware.