The Sheriff's gun changes from grenade launcher to high power rifle when he takes his son and girlfriend to the old ladies house. The gun in his hands then changes between these two clearly different types of gun several times thereon.
Just before the crocodile bites off Dale's arm, the tranquilizer darts disappear from its head.
When Scott and Carri hide from the crocodile in the house, it can be heard snarling outside as it retreats. When the two of them look out the window about one second later, the crocodile can be seen swimming in the lake, which is several yards away.
The plane used by Struthers is actually CGI, when showing a view of the lake from the campsite the plane isn't there. It is supposed to be by the boat! (at 29mins 19 secs min into the movie approx)
At about the 35 minute mark when the crocodile sneaks up on the cast after they've shot it with darts, the guide with the rifle brings his gun down to aim at the croc, then the angle switches and he does it again.
Repeatedly the crocodiles demonstrate the ability to submerge quickly without causing even a slight ripple on the surface of the water.
The description of a crocodile's death roll read by Struthers is incorrect. The purpose of the death roll is not to disorientate and confuse the prey, but rather to rip off a piece of meat for the crocodile to consume.
Crocodile nests are solid. They do not have access tunnels.
After the attack on the house we see 2 crocodiles swimming away. As there were only 3 giant crocodiles and 2 have been killed by then, where did the fourth one come from.
In the underwater shots of Emily swimming in the lake the water is blue and not green like water in a lake. The filming obviously took place in a chlorinated pool.
When the sheriff if first looking at Tillman's remains at the autopsy table, the cut-off leg wobbles in the coroner's hand, as it is clearly a rubber prop.
When the crocodile attacks the police patrol boat (after the boat 'hit a rock'), the digitally added splash effect is seen to appear through the unscathed floor, and cut through the Sheriff's legs.
In the beginning of the film when Tillman and Frank are talking to each other on the lake, just as they turn around, Tillman starts talking, but if you look closely, you will see that his mouth isn't moving at all to what he's saying.