I've noticed this weird thing. In each Mario series (excluding the first Super Mario Bros. in the Super Mario Bros. series), he runs differently. In SMB 2 & 3, he runs with his arms bent on each side and they stay still, and he tilts his body. In the Smash Bros. series, he bends his back and runs rather normally. In the 3D series, his arms are straight out to the sides and he bends his forearms as he runs. What running style is your favorite?