While Borderlands 2 feels like an incremental improvement in many way, one place where the jump feels much more significant is the visuals. The first game had a distinct and attractive art style, no doubt, but it was marred somewhat by low rez textures and limited graphics options, both carryovers from its console roots. This time around, Gearbox has obviously payed much more attention to the PC version in general, and especially in regards to graphics. Improved character models and much sharper textures really make the art style pop, while a greater range of effects only serve to strengthen the production.
However, the real standout if you have a high-end NVidia card is the game's implementation of PhysX. While unfortunately PhysX is limited to visual presentation as long as NVidia restricts hardware acceleration to their own cards, the eye candy it produces is still mighty impressive. Cloth reacts to bullets and bodies and can be torn realistically, liquids flow, and explosions produce tangible debris. The overall effect elevates the presentation and is impressive to the point where it might even sway some potential customers away from AMD's camp and towards an NVidia graphics card.