This is just me guessing do you want something like if say the world was a cirlce and that our feet should plant itself on the ground no matter what angle viewing.
then wasnt there like an orb gravity plugin ?
Many games today have exactly the system I want.. like Uncharted, Assassin's Creed, etc.. but the major are 3D. A foot is never floating, is always on the ground and the animations (walking, running, etc) adapts to the ground.. the legs, even with the animation, adapts to make the movements more realistic.
Here a video that is exactly what I want, but in 3D:
Look how at the beggining the character with IK walk adapting to the surfaces.