Borderlands 2 - Meet the Gunzerker @ IGN

IGN looks at the Gunzerker clas in Borderlands 2:

Every class can shoot guns, but they're distinguished by their primary action skills. The Gunzerker, for instance, can temporarily wield two guns at once. Build around these primary skills are elaborate trees that modify how the primary skill works. Gearbox's lead writer Anthony Burch and lead designer Jon Hemingway explain how.

So what does dual mean aside from being able to output more damage? According to Anthony Burch, "I can combine a shock machine gun and a fire shotgun and charge with my machine gun firing to drop [enemy] shields and then light them on fire with the shotgun at close range and melt their face."