So, there's 2 sides of the coin; 2D and 3D, but with 3D Land and 3D World, it's sort of a middle ground, and I don't know if it's even right to call the 3D Adventures a 3D Mario, more it's own thing.
If they aren't a part of 3D Mario, what category are they in? 2.5D? Do we start calling 3D...
Ok besides Champions Road and Mystery House Marathon what's your hardest Super Mario 3D World level. For me is Pirhana Creeper Creek After Dark. (Mainly The Very Stupid to get Green Stars...)