Continuity mistake: Kirk's arrow strikes the Klingon in the knee. But a few shots later, the shaft is protruding from his thigh, several inches above its original position. Still later, he's holding one hand to his calf just below the knee, which isn't where the arrow was either time.
Continuity mistake: The Klingon is standing on a hillside above Maab, yet when he fires his phaser, the beam streaks upward. From that angle, he wouldn't have hit anything but sky. Nevertheless, the beam somehow re-angles itself downward so that it hits and kills Maab.