"We really wanted to push the visuals on all of the maps. Each map feels very unique," says Dan Bunting, Online Director for Call of Duty: Black Ops and its upcoming multiplayer map pack, Annihilation, in a preview video for the Xbox 360's $15 / £10 June 28 download.

Four of the maps are for the standard multiplayer mode. Hangar 18 is centered upon a Blackbird SR-71 stealth bomber parked within the mysterious Area 51 military base.

"It has a lot of Easter eggs that play up to the conspiracy theory aspect," teases Dan, while level designer Paul Mason Firth promises both close quarters combat and sniper points.

Silo is the second map, a sprawling, snowy Russian construction site with many interconnecting paths and, according to fellow designer Phillip Tasker, favors players who "take their time, are smart, use decoys, and pay attention to the mini-map."

Both Drive-In and Hazard hark back to prior Call of Duty successes. Drive-In is inspired by the tight and frantic Black Ops original Nuke Town, while Hazard takes World of War's Cliffside, transplanting sniper-friendly scenery onto a sunny golf course.

As for the Zombies map, there's more than a hint of Indiana Jones about it. Set in (and named after) Shangri-La, players can commandeer mine carts, slide down water channels, set off spike traps and find themselves suddenly enclosed as shutter walls slam down.

Annihilation is the third map pack for Black Ops, with the other two having come out on Xbox 360 in February and April, making their way to PC and PlayStation 3 a month or two later.

By this time in Call of Duty: World at War's first year, two of three map packs had been release, so it seems likely that Black Ops will benefit from at least one more download before Modern Warfare 3 drops on November 8.

The Annihilation preview can be seen at youtu.be/rxX1v3bjXak.