This is very clever – it’s a zombie adventure story that gives you choices along the way, using the YouTube annotations to link to another video that reveals the outcome of the path you choose. Does the adventure continue, or does your choice lead you to become zombie dinner?
Also, it’s not revealed until the very end that the whole thing is an ad for a New Zealand pizza chain (which now makes sense, since the plot was a guy who was determined to deliver his pizza despite the zombie mayhem).