TedStixon

Revealing mistake: Jax and Sonya jumping away from the explosion when Cyrax self-destructs is just comical. The lighting on their bodies doesn't match the lighting in the background, revealing they were just filmed on a green-screen, and the background makes no sense whatsoever. The background is a blurry still image that doesn't have the same color-temperature as the exterior of the base seen earlier, with an obvious stock-explosion effect added over top of it that doesn't blend properly into the scene.

TedStixon

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.

TedStixon

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.

TedStixon

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.

TedStixon

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.

TedStixon

Revealing mistake: When Scorpion explodes, if you pay attention, the explosion doesn't really make "sense." The first "burst" looks fine, but then, midway through the shot, some of the debris in the air suddenly vanishes or fades out a few frames before the second "burst" occurs. Additionally, the way the second "burst" happens gives it away as an added effect, as it doesn't really overlap the background properly. (It looks like an explosion that was filmed on a blue-screen and then just added over top of the footage, as it doesn't interact with the environment properly).

TedStixon

Revealing mistake: When the scarab beetles surround Benni at the end of the film, watch closely... you can see many scarab beetles running directly "through" each other, revealing they are just a digital effect. (This is also visible in other scenes with the beetles, but it's most obvious in this scene, particularly in the first shot when the beetles begin to swarm towards Benni).

TedStixon

Revealing mistake: There is a mistake in the (quite dodgy) CGI when the car tumbles down into the dam in the opening scene. At one point, the camera cuts and we can see the car bouncing downwards through the air, and there's a splash of water from where the car bounced off the wall of the dam. But if you pay attention, the splash of water simply vanishes/fades away about two seconds later. Sure, if it was more of a fine mist, it'd make sense that it'd lose visibility, but these were huge streaks of water that should still be visible for quite a bit longer.

TedStixon

Revealing mistake: If you look closely, you can see the strings moving the Ouija board planchette while it's floating in the air towards Medea. (It's easier to spot them on the high-definition Blu-Ray version, but they can be faintly seen in other versions of the film if you know where to look).

TedStixon

Revealing mistake: When Pazzi is killed, there's a shot of his cell phone and phone battery slamming into the ground followed by a splatter of his innards. However, there is a (rather obvious and poorly timed) jump-cut in the middle of the shot, right before his innards splatter down from above. His cell phone is still moving about a bit, when suddenly it goes perfect still in an unnatural way. It also moves ever-so-slightly to the left when the cut happens. It's supposed to appear to be one continuous shot, but it's clear they dropped the cell-phone, waited for it to settle, then dropped the innards and tried to edit it so the shot moved faster.

TedStixon

Revealing mistake: When the mutants all run to Xavier and the helicopter towards the end of the film, it's blatantly obvious the actors were filmed running on a green-screen and then comped into the scene. The lighting on the actors doesn't really match the background, and somewhat more noticeably, they also don't cast any shadows on the ground.

TedStixon

Revealing mistake: During the scene in which Rasputin is resurrected, at one point, Ilsa wipes some snow off a wall then checks her book to see if she can match a symbol. When she opens the book, some snow lands inside of it... and it is incredibly obvious that the snow is fake. It looks like pieces of torn up paper.

TedStixon

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.

TedStixon

Revealing mistake: When Hellboy is seen filing his horns towards the beginning, as he runs the file along them (right before Broom takes the file), the prosthetic horn stumps are moving up and down unnaturally for a moment. As they are meant to be protruding from his head, they shouldn't be moving up and down as he moves the file back and forth.

TedStixon

Revealing mistake: When the elevator crashes down and Hellboy wakes up and starts to move, the prosthetics on his head move unnaturally around his horns and forehead as he gets up, revealing they aren't real.

TedStixon

Revealing mistake: After Jean kills Charles, Jean's house (which is suspended in the air) crashes downwards. Watch the scene very closely, and you can see some minor slip-ups in the computer rendering that give it away as a CGI shot. For example, some of the debris on the walkway in front of the house vanishes after landing. A very small piece of debris on the walkway is also seen "popping" upwards for no reason after having sat still for several seconds. Also, right before the shot ends, a few piece of debris in front of the middle window on the roof begin to flop about before flipping upwards in defiance of gravity. There are also several other minor issues with the shot. (Jean is no longer using her powers once the house falls, so this can't explain it).

TedStixon

Revealing mistake: During the opening chase scene, there's a few shots where Nick and Chris are running towards camera from gunfire in a few alleyways before they fall through a door. There's two shots where you can see bullets impacting the walls all around them, but if you look in the background, there's nobody there actually firing at them until a few people run into frame at the end of one of the shots. The bullets impacting the walls around them are literally impossible from this angle. Furthermore, during this scene, you can tell from the angle at which the bullets are hitting the wall that there's at least a dozen different shots that should have hit and killed Nick and Chris, but they escape completely unscathed. The staging of the shots is very poor and makes no sense.

TedStixon

Revealing mistake: Throughout the final fight between Pyramid Head and the Missionary, you can tell that Pyramid Head's mask and sword are very light-weight and made of rubber or another soft-material. Ex. When Pyramid Head hits Missionary out of the arena with the hilt of his sword, in the wideshot, if you look through the flames, you can actually see the sword bobbing about in the air before the tip hits the ground as the actor can't keep it steady.

TedStixon

Revealing mistake: During the final fight, when the Missionary is "sawing" through Pyramid Head's metal helmet, if you look closely, the helmet has been pre-scored and that the actress playing the Missionary is just running the blade along the pre-cut line in a "sawing" motion. The "metal" of the helmet also blatantly bends like rubber during the moment, revealing it's not really metal.

TedStixon

Revealing mistake: When the train crashes and then explodes during the climax, there's several major flaws that give it away as a pretty obvious and unconvincing miniature. First, the scale of the fire and sparks aren't right at all. Second, the cars it crashes through in the parking garage don't move normally or receive realistic damage when they're impacted, giving them away as very small plastic models. (You can see at least two cars simply being shoved along unnaturally.) And finally, when the train-car explodes, if you watch carefully during the second shot, you can see the (supposedly concrete) ground ripple briefly in an unnatural way at the start of the shot, and even see the train car wobble at the end of the shot, again very unnaturally, as the pyrotechnics make the small-scale model move.

TedStixon