I love the art style from Borderlands 2. I’ve seen it described as cartoony, cell-shaded, rotoscope-like, retro-futuristic and more, but whatever it is, it’s just really cool. Take a look:
I don’t think cell-shading is the best way to describe it, as it seems to come down to a lot of care and attention paid to the hand-drawn textures that are used throughout the game. it also makes really good use of bloom lighting on environments and enemies. The colour palette is very wide and can really pop, which is a huge improvement over the original Borderlands. Perhaps most importantly is simply the good character design. Gearbox established an awesome style and stuck to it in producing a huge array of quirky character and enemies. They almost have a steampunky look to them in places, despite the sci-fi feel.
I’m not good at dissecting this, so let’s just call it a glorious, colourful melange of awesomeness.