When Doomsday attacks the police, he kills one cop with his fists and then another by throwing a cruiser into him. When he lifts up the cruiser moments later, the second officer's body is nowhere to be seen.
When the submersible sub is ripped open by Doomsday, it is at approximately 6 miles below the surface, where the water pressure nears 16,000 lbs. psi. The pilot's bodies would have been utterly flattened upon exposure to this pressure, not left floating intact as if they were simply submerged in a pool.
When Aquaman investigates the crime scene under the deep sea, as he looks up ,sun light is visible. But in the deep sea it is completely dark as sun light can pass, at most, up to 1000 meters under water, and only under certain conditions.
(2:35) Dan turns to fire his gun pulling it from his left side since he is right handed. But the gun holster is located on the right side indicating he is left handed.