Official site here
The game starts off with your and three other players on a roof top behind a locked door. A nearby table is stocked with a selection of weapons, ammo and health packs. In the map we played, the first room had molotov cocktails, submachine guns, pistols and shotguns. Each player can equip a health pack, molotov cocktail, handgun and primary weapon: I went with the submachine gun.
Staying true to the zombie formula, your ammo is very limited, so survival isn't as much about clearing a room as getting through it.
After stocking up we unlocked the door, made our way down a set of stairs and were immediately attacked by a dozen or so zombies. The zombies in the game are a nice mix of the ambling Dawn of the Dead variety and the liquid fast 28 Days Later breed. The dead tend to stand around, mill in corners or, at times, crouch in pockets of shadow. Initially when they spot you they seem slow, turning to track you, but most of them got fast once they lock on and either run at you or, on occasion, actually leap across a room at you.