Factual error: When Sheriff Emmett Kimsey (Lou Diamond Phillips) and Dr. Sheila Casper (Dina Meyer) enter the mine shaft and fall down into the cavern full of guano, they light a flare. The flame would have caused the fumes to ignite.

Continuity: Near the beginning of the film when the sherrif is smoking a cigar and talking on the bridge, the cigar changes position every time the camera cuts between a close-up of him and a wider shot.

Revealing: In the scene where they are about to start that freezing machine, the dead body where they took the key from still looks fresh as compared to the others they examined that are in an advanced state of decomposition.

Continuity: Early in the movie when the Doctor is examining the teenager's dead body, his tie is first hanging down from his collar as he's bending over to look at it. Then the camera cuts in for a closer shot of him, his tie is now flipped over his shoulder.