Revealing mistake: During the sequence when Michael has his underwater motorcraft and the shark attacks him, you can see in certain long shots the machine which works the shark protruding from under its tail.
Revealing mistake: In the scene where the shark has Michael cornered in the old, rusted boat; as he's about to use his oxygen tank to rocket up to the surface, the shark breaks through the wall and when it does, a large number of thick tubes can be seen running into the shark to make it work.Clerk13
Revealing mistake: When the shark is rammed by the boat at the end, right before it explodes it is too obvious that the shark is a model. Some signs are: the oversized dorsal fins, its mouth is bent at an unrealistic angle, and it doesn't have eyes.
Revealing mistake: As the boat sinks you can see the rope attached to slow the boat sinking and control how it goes down. (00:10:45)
Revealing mistake: When the shark explodes, in the last shot (from behind the boat) which shows him exploding it is painfully obvious that the boat is only a model and not the real boat from previous shots.
Trivia: There are two different endings to this movie. In the first one (released on video and DVD in the US), the shark (inexplicably) explodes after being rammed by the boat and sinks to the bottom in a reuse of footage from "Jaws." When the camera cuts back to the survivors floating in the water, we see that Mario Van Peebles, though badly wounded, is alive after all. In the second ending (which can be seen on American Movie Classics in the US), Mario Van Peebles does not survive his fall off of the boat; when he falls, he lands in the shark's mouth and is killed. Also, when the boat rams into the shark, it does not explode but is more "realistically" impaled, blood pouring from its mouth as it dies. After the survivors are knocked off the boat, there is a shot of ship and shark sinking to the bottom, prow of the ship stuck in the side of the shark.