Zombies game

Cataclysm is really nice, if anyone here likes roguelikes. It has similarities to Project Zomboid, but it's waaaaaaay better. Doesn't look as good, though ;)

Fair Warning: The game doesn't have any graphics. Like dwarf fortress (superb game btw!) it's completly in ASCII code, but there are tilesets to give you a minimum of graphics. The site I got my tileset from is down unfortunately by now, but I'm sure it's still out there somewhere.

Plants vs zombies.

go for nation red gameplay

Zombier Grinder
Its free and online. In Pre-Alpha version, but pretty good.

http://www.twindrills.com/

KILLING FLOOR

Rebuild and Rebuild 2

Free

http://www.nomoreroominhell.com (damn, no luck with creating link...) - No More Room in Hell, Half Life 2 mod. Zombie-little-girls, melee guns who aren't cutting through everything with one hit, guns without tons of ammo laying everywhere, basicly your ultimate-zombie-experience.

Just wait for a zombie apocalypse like me bro :D

Dead Island, Dead Rising 1&2, Red Dead Redemption: Undead Nightmare

You can try with this new indie game about zombies, it´s simple but nice

http://www.threedeadzed.com/

Trapped dead, since I got one copy for trade:P

Keep an eye on Survivor Zero.

Dead State.

Two games that will be focused on surviving.

Killing Floor, thought there technically not zombies lol