Do not just spam click. Hold your mouse still to "focus" your ninja. Wait for an enemy to attack, then slice in the opposite direction of their swing. For gun-wielders, wait for the muzzle flash, then right-click to throw a shuriken into their head.
to download a Flash Player emulator that works on Windows and Mac. If you're looking for high-definition ninja action, the Ninja Gaiden series offers advanced combat mechanics on PC. download 3 foot ninja 2 for pc