Revealing mistake: During the Jax vs Cyrax fight, at one point Jax gets knocked down to his knee, and then Cyrax kicks him, causing him to fly upwards and backwards and roll over the top of the metal gurney. Except you can see plain as day that Cyrax's kick completely misses Jax. He kicks his leg about two feet in front of Jax's head.
Revealing mistake: When Sonya is facing the "extermination squad" while Jax fights Cyrax, watch closely. At one point, a ninja clad all in black does a jump-kick, which knocks Sonya back. Except if you look closely, he doesn't actually kick her. (It's really obvious when the camera cuts to a side-view and you can see he doesn't have his leg extended.) But they still add in a kicking sound and have Sonya react as though she's been kicked.
Revealing mistake: During the Scorpion vs Sub-Zero fight, after the ice-bridge collapses, when Sub-Zero jumps down to the lower level of the stone bridge to face his foe, you can see the floor beneath him ungulate as he lands, revealing there's a pad beneath the snow.
Revealing mistake: Cyras appears, who launches two spherical bombs that attach to the walls and explode. Watch very closely. There is a low angle shot pointed towards a doorway right after they explode, and you can see the set wall visible shake for a brief instant from the pyrotechnics. It can be hard to catch, but once you see it, it's very obvious.
Revealing mistake: During the Scorpion VS Sub-Zero fight, at one point, Scorpion kicks Sub-Zero and he almost falls into a lava pit, falling and wedging himself next to a stone pillar. (It's the bit where Liu has to jump across to save him.) When he hits the stone pillar, it wobbles like it's made of styrofoam, revealing it's not really stone.
Revealing mistake: In the beginning of the film, watch closely when Sindel says the infamous line "Too bad YOU... will die!" When Sindel says the words "will die," two of her teeth suddenly turn gray and become blurred. (One tooth on top and one on the bottom.) The best I can figure is that it was some sort-of slip up with the special effects rendering, since the background has a CGI sky replacement effect. It can be hard to notice at first, but if you know where to look, it's pretty obvious.
Answer: This could have been a mistake but then again it could have been one of the people inside of him just stepping up and saying it to keep Shao Khan from throwing them over with Rain.
Rollin Garcia Jr