Revealing mistake: When Tony goes to the bathroom and scans his blood toxicity, the Tony who faces the camera is supposed to be his reflection in the mirror, but the problem is the reflection is not reversed because it's not a mirror image, note Tony's clothing. Also, note how he scanned his right hand's finger, but then in the "mirror" he's sucking on his left hand's pricked finger. (00:28:30)
Revealing mistake: When the 2nd BMW SUV is blown up on the dock, you can see the underside of the vehicle which reveals how they removed the drive shaft to help reduce the weight of it in order to flip it easier. There are also 2 jets of white gas seen coming from 2 pipes under the rear bumper which are what launched the vehicle end over end.
Revealing mistake: When Alice and Claire land on top of the prison in the plane, Angel pulls a cable across the roof to help the plane slow down. As he pulls it tight the angle at which the camera is at wobbles due to the cable knocking it. (00:31:50)
Revealing mistake: Towards the end of the movie, when Steve Austin is on fire during the fight, you can see it is a stunt man wearing a burn suit for a split second.
Revealing mistake: When Travolta is fighting the Asian gangsters in the alley, he disarms one of the thugs by taking apart his opponent's gun. You can see that the Beretta pistol is partly disassembled before Travolta even touches it. (00:28:40)
Revealing mistake: Inside the tunnel, Roy is on the car's hood, with the car swerving all the time. When the angle changes to a POV of the baddies he doesn't move, as if he was glued to the roof, revealing the security trick.
Revealing mistake: In Frank and Sarah's first conversation her headset is on mute, shown by the fact it's blinking red. (00:02:25)
Revealing mistake: In the beginning, during the press conference, there's a press photographer taking pictures. He's obviously an extra with no experience in DSLR cameras at all, holding the camera around the flash and lens. He pushed buttons on the flash to "take a photo" and not one finger actually moves the real trigger on the upper right of the camera body.
Revealing mistake: When Cuchillo is about to be shot by Isabelle, you can see the bullet-hole-effect go off too early, due to bad editing. It's exactly in between that scene, when both actors are from the side, and as the scene changes to where Isabelle is seen from the front. (00:34:25)
Revealing mistake: After the prince is crowned king, Robin and his mates leave the castle. If you look to the upper-right of the screen, atop a hill in the distance, you can see a modern-day metal telegraph tower (cinematic version).
Revealing mistake: The guns that the soldiers use to kill piranhas with are actually Nerf Longshots that you can buy at the toy store.
Revealing mistake: When Salt sits on the helicopter there are two of the same cuts with Salt looking through the heli's window with yawning guy in the background. Cuts split by the view of Washington DC.
Revealing mistake: When Dominic West is captured and chained in the Pict village, you can see a hearing device in his ear. (00:38:55 - 00:41:35)
Revealing mistake: Throughout the movie, people getting shot almost always don't have the shot angles line up with how they appear. This is especially obvious in the end scene with Hit Girl shooting the gangsters: she might shoot someone at an angle from the side, but the shot appears to have come from directly behind the person.
Revealing mistake: When Mike shoots the cop in the beginning you see him fall on a mat to cushion his fall.
Revealing mistake: Throughout the phonecall between Killer and Lucy, the call duration on the iPhone stays the same at 00:03. (00:37:00)
Revealing mistake: Horvath is trapped in the bathroom mirror, and after knocking on the mirror from the inside, a boy comes over. You can see that the shadow from the boy's shoulder is falling on Horvath, and when he turns and falls over, if you watch closely, you can see that the boy bumps into Horvath's arm. This is because the boy actor is standing in front of Horvath's actor to achieve the mirror effect.
Revealing mistake: The handheld device that Bob uses to adjust the satellite antennae is actually a very common label maker and printer sold in most Walmart stores.
Revealing mistake: At the end scene when the Sheriff is escaping in the truck away from the nuclear blast, the truck begins to flip through the air. While it is flipping we see under the vehicle and can see the hole they use to launch a post to help flip the vehicle for the stunt. A brief puff of white smoke also emanates from that hole briefly during the flip.
Revealing mistake: When Jensen is investigating the missing 4 million dollars from the account, we see the screen on his laptop. Among other things, it shows a picture of Fadhil's passport, which looks like it has a watermark on it, readable as http://slawek.com. Indeed, going to http://www.worldpassports.org/americas/pages/bolivia.htm you will find the passport pictured there. (01:01:35)