BioShock 2 single-player DLC due Aug. 3

Since BioShock 2 debuted at retail in February, it's shipped over 3 million units, injected two multiplayer packs, and helped GameStop post its biggest non-holiday ever. But publisher 2K doesn't want the maritime onslaught to end there.

The company today announced single-player add-on content for the disturbing underwater shooter. Unlike its predecessors, the Protector Trials downloadable content (400 MS points, or $5), is a single-player affair. It has the game's Big Daddy protagonist defending Little Sisters from waves of mutated Splicers trying to thwart the little women's ADAM collection. The scenario, a cross between Gears of War's Horde mode and the Resident Evil series' Escort modes, was used in several set pieces during the game.

The action will take place on six "new" maps based on locations from BioShock 2's singe-player narrative when it comes to PlayStation 3, Xbox 360, and PC August 3. Also up for grabs in the content are three difficulty levels, concept art and videos to unlock, and seven new achievements/trophies for players to collect.

The Protector Trials DLC follows the Sinclair Solutions Pack, which brought several weapons improvements and other upgrades to the game's multiplayer component, and the Rapture Metro Pack, which added several new multiplayer maps.

According to 2K, the battles won't stop there. The company promises additional downloadable content that will extend the single-player experience and provide "new insight into the world of Rapture."

For more on BioShock 2, check out GameSpot's video review (embedded below).