Revealing mistake: After the woman is strangled and the people come in trying to find the little kid, the dead woman is clearly seen blinking. (00:11:25)
Revealing mistake: Cross is between the first two steps of his tour de force following the instructions for the diamond delivery. McArthur says "Unit six, take "K" Street and double back", and we are shown Jezzie in her vehicle. She moves cutting through a traffic island with a forbidden maneuver, and yet you can see on the asphalt wet marks of 'someone' doing the exact same thing before her recently (obvious residual of the previous take). (01:06:30)
Revealing mistake: During the botched save of agent Fisher, the helicopter with the spotlight is well behind Cross and the others, and yet the light is projected on parts of the bridge who are facing away from that light and in fact blocked by the bridge structure, as if a strong light source was coming from the front of the rescuers. (00:04:40)
Revealing mistake: In the van at the beginning of the movie, Cross is checking out newspaper clippings about the serial killer. When they are shown in close-up for a couple seconds, the two leftmost clippings, that Cross took his time to pick and hang in the van, are obviously the same article with different titles (both in a single column strip, they even have the same layout and division in paragraphs, it's easy to spot even if you don't repeatedly watch or freeze-frame to actually read, and you just need to glance to see that they even have the same author listed). (00:02:50)
Revealing mistake: At Mercusio's place, Cross is checking out a variety of material the maniac collected on Cross himself. Which include newspaper clippings but they're all the same one, by "Lisa Francescato", same article repeated, just omitting the first short paragraph the second time. (00:39:20)
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.