Call of Duty: World at War: Zombies took us by surprise when it suddenly appeared on the App Store last November. Given that it was a big console licence, ostensibly ill-suited to iPhone, and introduced to the world as coyly as one sneaks a soiled blanket into the in-laws' laundry basket, we expected it to be rubbish.

Surprise number two: it wasn't, and it went on to sell gangbusters, making Activision an enormous pile of money that it probably wasn't expecting to get.

So, naturally, there's more. Activision today revealed to Kotaku that the Verruckt map pack will be available on the App Store tomorrow. Like its home console counterpart, the iPhone version of Verruckt will be substantially larger and, in principle, more interesting than the original game's single map.

The co-op multiplayer is also much improved, according to Treyarch community manager Josh Olin. "You need to work as a team," he says. "If you play four player, you spawn on two sides of the map and work your way to the power room where you can flip on the power switch that will turn on the perk machines."

The Perk a Cola machines he refers to dispense perks, weapons, electric barriers, and sounds.

Sadly, all this doesn't come cheap. The Verruckt update will cost you £2.99/$4.99, bringing the total cost of the game with both maps up to £8.98/$14.98. With several more maps coming, it looks like you'll easily be able to drop a home console-size chunk of money on Call of Duty: World at War: Zombies if you're not careful.

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