The ‘Creature Slaughter Dome’ trailer highlights a GameStop pre-order incentive, available only if you pre-order the game through Gamestop. In the Creature Slaughter Dome players get a chance to kill more creatures, gain experience and keep any loot they find back into the main game. Endure the battle, and you will receive NUMEROUS rewards. The pre-order also includes a special gun called Moxxi’s Rocket Launcher. Other exclusive bonuses for pre-ordering (these features and items available for all pre-orders not just Gamestop or Ebgames!) are: Borderlands 2 Premiere Club, Golden Key, Vault Hunters Relic, Gearbox Golden Guns and the Mechromancer class player.
Article from Gamersyndrome.com