She blows a kiss to destroy the barriers that prevent her from proceeding to the next area. But I just learned she can stagger opponents by holding the lock-on button. So... I'm gonna go try that in the demo now. I recommend anyone with an Xbox 360 or PS3 with a Japanese Account to download and play it. Aside from the kiss stuff it's a great action game.
I can't find a video of the staggering kiss but every demo playthrough on youtube shows the barrier breaking kiss.