Revealing mistake: When Hawkins is pulled into the lifeboat by Long John Silver, if you look closely, you will see that it is a stunt double who is doing the falling.
Revealing mistake: Just after Roy Nord gets killed in the mid river passage collapse, we see one of the criminals and Kit come out of the hole, and the black criminal get thrown back by a big flame explosion. When he hits the wall, it seems to bend. (00:50:35)
Revealing mistake: Look at the gun fired behind Shale at the firing range. The person doesn't pull the trigger, there is no flash, the slide doesn't move, there is no smoke. But the gun still kicks.
Revealing mistake: When Ethan uses the magnetic screwdriver to undo the screws holding the grille to the air-vent in the NOC list room, the spindle that is actually turning the screw is visible after it falls out.
Revealing mistake: Certain parts of this film were made during the spring months, not winter. In the background of the high up shots during the parade, leaves can be seen on trees (in the distance). Also, the grass is surprisingly very green, in several locations.
Revealing mistake: When the policeman is shot on the roof of the observatory and the police cars drive across the grass, you can see the tyre marks in the grass from previous takes.
Revealing mistake: After Seagal and the student jump off the window they land on the floor and for a brief but obvious moment one can notice it's not Seagal but his stunt double.
Revealing mistake: When Diana is about to jump off the plane onto the galloping horse, her hair moves wildly. When the shot changes, she has been replaced by a stunt who looks nothing like her and has her hair fixed.
Revealing mistake: When Kiki's legs "reverse" at the end of the film as he runs off, watch closely. It is clear the effect was achieved through some shoddy image-manipulation. His clothing and hands "warp" slightly a few times around his legs.