Since the industry's shift to 3D in the 32/64 bit generation 2D titles have been shamelessly neglected by the majority of developers. With the move to three dimensions it was widely believed that 2D games were not bankable and best left on handhelds, the real opportunities had moved to the third dimension. For a decade the great 2D efforts have been few and far between, but things have begun to change in the last few years.
New Super Mario Bros. proved to Nintendo that 2D was still viable, and the DS as a platform has had more then a few excellent 2D titles. Just this year, Odin Sphere and Super Paper Mario have spearheaded 2D's revival on consoles and are proving that style of gameplay is far from finished.