Continuity mistake: David Sloane (Sasha Mitchell) is the brother of Kurt and Eric Sloane (shown in Kickboxer, with Jean-Claude Van Damme). In the opening scene you can see pictures of the brothers, but the Kurt and Eric Sloane featured on the photos are NOT the Kurt and Eric Sloane from the Kickboxer movie. You also see pictures of Xian and Mylee, from 'Kickboxer'. Then later in the movie, when David and Xian 'meet', David asks Xian, "Who are you?" Well, he would obviously know, given that he's got Xian's photo hanging on his wall at home.
Revealing mistake: When David delivers the final kick to Sanga, he raises his left leg to kick but in the next frame it is his right leg which comes out and makes contact to Sanga's face. The right-leg is also a prop made of rubber as you can see the crews hand holding onto the thigh part and the rubber foot flopping/wobbling when contact is made. The following frame shows David bringing back his left leg after the right-legged kick.