Factual error: When the shark is chasing Mike and his girlfriend near the end you can see air bubbles coming out of the fin (obviously a hole in the puppet). Real sharks do not blow bubbles from their fins.
Revealing mistake: The shark attacks a little wooden platform in the water which 3 men then fall through. You can see this is made from a lightweight wood such as balsa so that it will break apart easily, and it's not the sort of wood such a thing should be made of.
Factual error: At the end of the movie, the shark broke through the glass. When the entire room was flooded, the shark grabbed someone and started chewing them. Sharks don't chew their food. If their prey is too large to swallow whole, they rip it apart into smaller pieces.
Factual error: In the scene where they try to lure the shark, it eats that man. How is it possible to fit in a shark's mouth when only someone's leg did before? Also, if you look outside the shark's mouth, it isn't going anywhere, which is also impossible.
Other mistake: When Jaws breaks the glass in the control room, it shatters and flies everywhere, but the water doesn't even move or give any indication of flooding the compartment.
Revealing mistake: When the shark crashes in the control room and eats Fred, "Fred" is a dummy. His hand moves around in the water in an unnatural manner.
Factual error: The scene where the Shark is in the water/air circulation pump it swims backwards out of it. There is no way a shark could do that, it would drown.
Continuity mistake: When Mike has the harpoon pointed for the sharks dorsal fin, there is white rope wound around the length of the metal harpoon. In the shot just before he shots the harpoon, there isn't.
Continuity mistake: When the shark is chasing the water-skiers, you can see its fin is about 3 feet behind them, meaning its head must be underneath, if not in front of them. However, in the shot from under the water its viewpoint is shown as being behind them.
Revealing mistake: When the baby shark smashes into the gate, not only is it a dummy by the way it looks, but the head actually compresses back into the body on impact.
Revealing mistake: When the baby shark dies it is an obvious fake rubber shark with no movement before it died and no reaction from the watching crowd.
Audio problem: Near the end of the film when the shark is in the control room he eats a man underwater. The man is heard to scream and cry out, and you can hear him taking breaths in between screams despite being underwater with no breathing equipment.
Revealing mistake: When the shark goes on a rampage at Sea World, whenever the fin goes above water, it is blatantly obvious that the fin is fake, and it is doubly obvious in some shots when we can see the welding line running right down the fin where the crew fused the two sides of the fin together.
Factual error: In the scene near the beginning of the film where a diver gets eaten by the shark, an unattached arm is left suspended in the water. Not one drop of blood was spilt into this water.
Revealing mistake: About two-thirds of the way through the film, there is a wide shot of Jaws swimming. Keep in mind that a shark swims by the moving of its body and tail. It's quite obvious to see that Jaws is a matted-in puppet as his tail moves only once and he is propelled a long distance. Also note the fact that the tail move is quite mechanical and not the easy motion a real shark would make, and his body doesn't move at all. The shark in Shark Attack 3: Megalodon looked better than this.
Revealing mistake: Matte lines are visible on the submarine as Mike and his girlfriend drive it through the reef.
Revealing mistake: Very obvious fake dummy when Mike and his girlfriend view the dead body.
Revealing mistake: Matte lines are visible around Jaws when he crashes into the window of the control room.
Revealing mistake: When Shelby's corpse shows up in a Ben Gardner like jump scare, you can tell that the hair is not attached after they made a mold of Harry Grant's chest and face and edited it.
Continuity mistake: After the big shark dies Mike and the blonde girl are calling the dolphins, in one shot it's dawn and it's dark but suddenly in the very next shot it's completely daylight.
Answer: You are correct that he never directed another movie because Jaws 3-D underperformed financially and was a critical failure. Alves' directing style was particularly panned. As a further humiliation, Alves was nominated as 'worst director' for the 1983 Golden Raspberry Awards.
raywest ★