Revealing mistake: When running towards the "bear attack", Sean activates the Guyver. Close ups of the armor attaching itself to his body show that's not really Sean as his arm and leg are both seen not moving even though he's running to where the attack is occurring.
Revealing mistake: When Picard is trying to squeeze through the rock archway, he looks like he's stuck, but a closer look reveals he has enough room above his back to squeeze through without any trouble.
Revealing mistake: In the scene where O'Neil is fighting Ra's bodyguard, the bodyguard uses claws and hits O'Neil's back, tearing his shirt and wounding him. But you can see Kurt's "wounds" and torn shirt right before he's hit by the bodyguard (a scene after Ra's bodyguard's claws are shown). (01:49:10)
Revealing mistake: When the team are heading back to base and we see the skyline for the first time, it's obviously a painting projected onto a blue screen. You can see the line where the set and the screen meet. There is also a white line running across the bottom of the screen. (00:24:50)
Revealing mistake: As Mary, Sam, Jarvis and Andrew are speeding away from the TV station, one of the boys from the UFO crashes his bike head first into the car. This causes the boy to crash through the window. When he does this the window shatters like a plate glass window instead of the safety glass that is a standard to be used for vehicle windshields.
Revealing mistake: Toward the end of the film, when the bad guys have invaded the good guy's camp, note the scar on the forehead of the lead baddie. The prosthetic scar is very obviously not real.
Revealing mistake: When the doctor is stapling the head, the staples are pre-attached. Also, he stops midway in the close-up shot. (00:37:38)
Revealing mistake: When they are stopped after curfew by the Mohawks, Hawk jumps at the window and orders them to give them 50 bucks to go on, and they accept credit cards. When saying this, you can see the dividing line between his real skin and the fake head cap that supports the actor's fake hair.
Revealing mistake: Near the beginning, when Van Damme goes and arrests his former partner, watch when they both jump out the window. It is clear that they are on a cable decelerator. They fall straight down and in a controlled and slightly slowed motion. Very noticeable.
Revealing mistake: When Willie's body is covered, you can see the little boy playing him scrunch his eyes tighter shut and he smiles very briefly.
Revealing mistake: When Alex throws Banes at the lab, you can see the stunt double falling for him.
Revealing mistake: Most of the police cars are late model Ford Sierras, but any police car that crashes has been substituted for a much older early model Sierra.
Revealing mistake: During the opening, where we see a new Tall Man emerge from the portal and toss his decomposed body from the second movie into it, the actor's reflection is visible in the metal portal poles as he waits for his cue to 'materialize' in the room.
Revealing mistake: At the black market, Honda and Balrog bring Ryu into the tent that Ken is already restrained in. When they enter, Ryu begins to fight with Honda and Balrog but Chun-Li ends their fighting by emerging from a curtain wielding a knife. Ryu backs into the knife and it bends.