Superman raises the bathysphere in which he is trapped along with Lois, Jimmy and Mr. White by hauling the cable into the bathysphere through the small hole in the roof. But he's standing flat on the floor as he does it. He would have to be braced against the ceiling (or some other fixed part of the structure) in order to move it upward.
Mr. X says Lois, Jimmy, and Mr. White will be crushed at 250 feet deep under water while a man has gone 700 feet deep without any equipment.
Superman didn't need to raise the bathysphere up using the rope or cable that it was attached to. As Jimmy suggested he could have pushed it up and his reasoning that he'd have to do so from the outside of it isn't supported by physics. He could have pushed it up from the inside just the same as from outside of it.
When Lois, Jimmy, Superman and Mr. White are once inside the bathysphere and dropped from the side of the pier to the bottom. Mr. X says they are now 250' below the surface, when in fact there are no piers anywhere where the water is that deep at pier side.
In order to stop the crooks plan, why didn't Superman first fly to the bridge and just pull the burning fuse on the dynamite and save the bridge and his wife and he would not have had to stop the armored truck as well.
Lois tells Superman she can't get the door to budge when they get back to the surface yet it can be seen wiggling when she tries.
For apparently not many lights in the bathysphere there are some very strong shadows being cast on the inside walls of it.
Metropolis is supposed to be on the East Coast of the United States, and yet, the armored truck is passing through a desert on the way toward town. There are no deserts on the East Coast.
After the others have exited the bathysphere Lois tells Superman to come out and he replies if he lets go of the rope it will sink back to the bottom so he will let go and swim up after it sinks. Why? Either way it will still be on the bottom. And anyway he could have just as easily exited the bathysphere while still holding the rope and tied it off to keep it from sinking.
Near the end Jimmie Olsen says to Sergeant O'Hara "You're a brave man". Sergeant O'Hara is, of course, a woman.