I don't know how to quote a post when a thread is locked but let me copy-pasta a reason why I've got this hype for the zombie genre.
"Hey, lets not bash my views but the reason I would want zombies is to explore the dark and grittiness of LS, All the bright lights gone off, fires and wrecked cars in the streets, army squadrons attempting to fight the hordes, seeing cars drivers speed like maniacs to escape, military/police blockades/checkpoints, or just going though the subway/tram (I don't give a sh*t) tunnels while it's pitch black only to rely on your guns flash light. LS's celebrities would be all DEAD (Good grief, f*ck those celebrities) seeing people get eaten and seeing just the ruined city.
Don't forget the countryside, cluttered highways, derailed freight trains, gangs holding off their turf, and what about multiplayer with zombies? riding a vehicle convoy with a view players while making sure you guys don't get jumped when you pull over, or driving with one friend while a zombie clings to the hood and tries to kill you both while you frantically try to shake it off while your friend tries to blow it's brains out but just can't. Or staying inside a building, hiding while waiting for the zombies to leave, or trying to evacuate fellow players during a harsh moment, or just plain KoS because someone tried to look for Twinkies in the back of a van and then went on a crazy rampage killing everyone.
Sorry, I daydream to much. Much you see what I care about, Immersion, Horror, rain, destruction."