When Whitlock is first bitten, his arm is severed at or just below the elbow. In subsequent scenes, the remainder of his arm gets progressively shorter. In the last scene before they exit the elevator, there is only about 6 inches of arm left below the shoulder.
Carter pries open a door with a knife that is on a sheath on his leg. The knife breaks and he throws it away. In the final scene, when Carter and Preacher are laying on the wreckage, the knife is clearly visibly back in the sheath on Carter's right leg.
Towards the end of the movie when the carter, preacher, and Susan are about to make the long swim to the surface, right after the air tanks deploy, the first close up of Susan waiting for the others clearly shows Susan's head about a foot beneath the surface of the water, when they are supposed to be 60 feet under water.
When they are extracting the protein from the shark, the monitor displays real-time MRI imaging showing the insertion of the probe into the shark's brain. This is impossible, since they removed the imaging device before placing the probe jig.
When Carter first grabs the "Tiger" shark's Dorsal fin as he tries to remove the license plate, there are several wide shots that show he is too far from the mouth to be able to reach the plate, which would be accurate with the portrayed size of the shark. In the close-up shots, he is still holding onto the dorsal fin, but is able to reach the mouth.
The above water fences were shown to be of the chain-link variety. Which is wire strands bent in a zig-zag pattern and interlinked to form a diamond pattern. However, when it was revealed that the sharks were sinking the facility to escape through the weaker, above water fences, the fence that the shark was tearing apart had a square pattern (resembling the flexible, titanium underwater fence), and the shark was pulling long, straight strands out of the fence.
After the three wet-suited survivors have been hoisted out of the elevator shaft by the use of knotted-together linens, the makeshift rope can clearly be seen hauled in behind the door that is subsequently shut tight. In a later shot the linens can again be seen hanging out of the door, which remains shut.
Near the end of the movie, Carter is swimming back to the wet lab through flooded passageways. At the beginning of the swim, his left shoe is completely untied - you can see both laces floating. In the next full body shot (where his shoes show) the shoe is tied again.
In the beginning of the movie with the party on the boat and the Gen 2 shark attacks the boat. On the boat the people are listening to a boombox with a teddy bear on it, as the sharks attacks the boat the boombox falls of the boat and into the water, but for a split second the camera shows the boombox still on the boat in its original place.
Towards the end when the three remaining survivors try to get to the surface by escaping through the water filled shaft, when they are coming out of the shaft door, a crew members legs and red swim shorts are clearly visible and in fact at one point block the entire shot. The three survivors at that point all had long bottoms and none of them were red.
At the end of the film, Dr. McCallister jumps into the water having cut her hand to attract the attention of the shark with her blood. The time taken for the shark to detect her blood is extremely short - far, far shorter than the time it would take for it to diffuse through the water even if there were considerably stronger currents than were visible.
During the Climax of the movie, the survivors make an improvised explosive using the black powder from 10 flares. One of the characters mentions that they could get 2 1/2 sticks of dynamite form the flares. In truth the flares they're using each contain only about 1.5 grams of black powder. They would need 450 of those flares to get the equivalent of 2 1/2 sticks of dynamite.
Many times we are shown people able to close doors even though copious amounts of water and air are rushing though them. This is clearly beyond the ability of humans. Their ability to do so cannot be explained by other devices attached to the door because those devices would have prevented them from opening the door in the first place.
Titanium, space-age material though it is, is only stronger than stainless steel in a strength to weight comparison. For a given cross-section (or wire thickness), the two metals are comparable in strength. There is thus no need to use this pricey material for fencing.
Carter Blake rubs the body of a shark back and forth with his bare hand(s), as if the surface were smooth (as that of a dolphin). In fact, shark scales are quite rough, and this kind of petting could cause the hand to bleed. At any rate, Carter would not be able to pet the shark with as gentle a motion as he was in the movie.
The "tiger shark" near the beginning of the movie is not shaped like a real tiger shark even though the movie shark has similar markings on it's back. A *real* Tiger shark has a blunt rounded nose, and jagged odd shaped teeth. The Tiger sharks in the movie are re-dressed Mako sharks.
When the kitchen level of the facility is flooded, the water comes rushing down the stairway and into the open hallway. Shortly after this, Preacher wades through the flooded hallway and kitchen in waist-deep water; this should not have been possible because if water was rushing in from the ocean above and the level above it was flooded then the water should have continued to flow down into the corridor until the lower level was completely submerged.
When the researchers are extracting the protein from the shark, the shark's ECG (electrocardiogram) tracing is shown on a vital signs monitor. Not only is the tracing being refreshed right to left, i.e. backwards (which is never done on a real monitor), but the ECG pattern itself is not that of a shark.
After Susan electrocutes the shark while in her underwear, she looks at the research data that has been destroyed by the electricity. It has been burned and shows carbon stains as if it had been in a fire. This could not have happened while in water and the data probably would not have been damaged at all from an electric charge in the water.
When the door from the sub pen into the elevator shaft is opened, there is a gust of wind into the actors' faces from the shaft into the room. If the sub pen were actually pressurized, the wind would have come from behind the actors and blown into the shaft, as the air pressure in the shaft would have been lower.
When they open the door to the shaft when being in the docking area, there is a couple of seconds delay before the water starts rushing into the room. That would have happened instantly. This cannot be explained by some hatch/door/similar collapsing farther up the shaft because this would have caused an immediate and very noticeable rush of air into the shaft.
Just before the experiment and moments before they witness the sharks swimming backwards, they are monitoring Carter as he swims through the protective tunnel. All of the cameras shown are fixed and mounted to the tunnel yet for a brief moment the camera monitors show a backwards tracking shot moving along with Carter, clearly shot by the film crew swimming in front of him. In fact a very similar shot is then shown as part of the movie, showing recycled footage being played on the monitors.
When Preacher shoots the shark with a harpoon, it goes through the shark's dorsal fin and supposedly impales Carter Black's right thigh. But in the next shot, just before the shark submerges, you can see the strapping arrangement used to fasten the harpoon tip on top of his leg.
The goof items below may give away important plot points.
At the end when Preacher is attacked by the shark, he is bleeding profusely. When he is rescued by Carter he is surrounded by his own blood in the water. However, when Carter drags him to the cement wall to get him out, the giant pool of blood is gone.
In a test screening one month before the film's opening, the ending
had Susan (Saffron Burrows) escaping the shark at the end and saving
the day with the spear gun. Audiences booed that ending, and sure enough, it
came out with Susan getting eaten and Preacher (LL Cool J) saving the
day. You can actually tell that some of the final shots were three-shots,
with empty space where Burrows would have been. Sometimes
Thomas Jane's eye-line looks like it should go to her. She's been