Originally Posted by Kotaku
In this frozen land, we saw the Gunzerker fight Bullymongs, four-armed monsters that threw rocks and ice at the player. Those attacks represent a portion of the AI improvements in Borderlands 2. Enemies now attack differently. They navigate terrain differently. They’re smarter about taking cover. And they can be stunned, knocked down and suffer from injury in combat. Gearbox illustrated portions of those improved combat mechanics in another section, when we actually run into the aforementioned W4R-D3N.
Explodable disposable guns
Dual-wield assault rifle guy is a dwarfish char named "Gunzerker"
Lots of AI improvements
Borderlands 1 chars return as part of story in b2
Psycho midget meatshields
New gun manufacturers, including Bandit made "DIY style" guns
Vladof "bullet hoses" that ramp up in rate of fire
New "less questy" missions, more adventure
Ultra Disposable Gun One Of Little Improvements In Borderlands 2 | Kotaku Australia