Ever since the fall of Lair, Sony has been reluctant to tout the SIXAXIS functionality of the PS3 wireless controller. It's no longer a marketing bullet point, and even if developers offer support for motion control, it's usually turn off as a default. (Most recently, Batman: Arkham Asylum let players use SIXAXIS to control Batman's glide.)
While other developers ignore the SIXAXIS, Team Ninja isn't afraid to highlight its unique implementation of motion controls. In the first Ninja Gaiden Sigma game, players were able to cast magic by shaking the controller violently. This time around, the shaking has an entirely different (but equally important!) effect. You probably should have figured it out from the headline and IGN's cleverly constructed image. If not, there's a video after the break.