The wraps have been taken off Left 4 Dead 2's funland setting, with information on new special infected, settings, objectives and...clowns.
The campaign - Dark Carnival - takes place across a variety of locations, from a hillside to a hotel to the carnival itself, where Valve promises that some of the attractions will be actually functioning, and playable.
As far as new stuff goes, there's an electric guitar to use as a melee weapons, a clown zombie that's able to call other zombies over to him and a new special infected: the jockey. Who does what a jockey zombie would be expected to do, and jumps on a survivor's back. To ride them.
While a jockey is on a survivor's back, the player loses control, and is usually steered away from their pals and towards a horde of zombies.
Left 4 Dead 2's Dark Carnival unveiled [Eurogamer]