Whenever you're controlling Kai and are going for points (and hence a full gauge), you can score more points by attempting multiple hits on each of your foes. Body shots are only worth six points, while other non-head shots are worth eight points. Headshots are worth nine points. So, try to hit a soldier in the legs to knock him down, scoring eight points, and then score a headshot to get another nine points (for seventeen total). Scoring headshots right off the bat will actually take points away from you. Then again, some can be shot again when they're dying on the ground for additional points.