Well, you see the credits rolled and people got up. Some picked up their popcorn buckets and half eaten boxes of raisinets...
Oh, you mean how did the film end? Superman flies around the earth super(there’s that word again!) fast, causing time to flow backwards, thus keeping Lois Lane from being killed.
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I seem to remember Supes dropping Luthor and Otis off at a prison, with Luthor taking off his wig and about to declare that “these walls” presumably would not contain him; rather goofy conclusion. That was after Supes interfered with the planet’s space-time continuum.
I remember reading some time ago a different perspective on that scene: Superman was going so fast that he was time-traveling.
Unfortunately, the angle they chose made it look like Superman was physically making the Earth go backwards, and THAT was causing time to reverse (which is ridiculous, and would cause a rather horrific cataclysm).