I've been playing this game for about a month now. It's set in a post-zombie outbreak city, where survivors fight against zombies. There's a duality between the two factions: survivors that die rise as zombies and zombies can be revivified by survivors (those with the Necrotech skills and items).
You get 50 action points a day (one per half hour) to perform actions like moving to a new block, using items, barricading a building, searching for items, and attacking another player. There's an RPG sort of XP gain and skill tree progression; one skill tree for survivors and one for zombies.
What's really cool is the amount of organization that the players have put into it; emergent gameplay is the buzzword. The official wiki where players debate city-wide barricade plans, update current danger status maps, debate survivor and zombie tactics, discuss the role-playing validity of survivor-on-survivor attacks, and list an extensive glossory of game terms.
There's also appears to be quite a history of cool stuff players did.
- First Siege of Caiger Mall (complete with t-shirt)
- The suburb of Ridleybank, a zombie stronghold held by the The Ridleybank Resistance Front
- There was a city which had the Big Brother House (from that reality TV show). Survivors could barricade themselves inside from zombies, and any one inside of a mall could turn on a TV to see the status of the Big Brother lounge.