all happening live as the "player" talks the main character through the actions.
My favorite bit mightttt be at 4:21...."shoot the guy at the right cleaning his car." Haha! Smart player, always trying to find a way to expand the game past its intended realm. I also really love when he was instructed to play the organ, and the sound guy layered on some appropriate playing. It reminded me of Resident Evil games where your character takes a break from fighting off mutant zombie to just play some piano. Real casual.
Want to know how they did it?
They wanted to make a live action FPS. And let the player actually get to control it! I have to say they pretty much succeeded at accomplishing all of their goals.
The amount of work that went into something like this is amazing: they had a sound guy live layering sound onto the video, an actor running around with a go-pro and video encoder strapped to his head, a zombie following him with a router, a voice actor, a video editor, and more all running around to make the action come together live!