I came across this today. It's cute.
If you remember the first Superman movie, with Christopher Reeve as Superman and Gene Hackman as Lex Luthor, at the climax Luthor tricks Superman into coming after Luthor in his lair. Superman confronts Luthor, who tells Superman his plan to send the U.S. West Coast into the ocean with a nuclear missile while another nuclear missile was headed for New Jersey. Superman scans the room with his x-ray vision looking for the destruct button, discovering that Luthor is sitting on a lead box. Figuring this is where the button is hidden, Superman throws it open and is bathed in the radiation of the kryptonite hiding in the box. Superman collapses, Luthor leaves. Luthor's minion, Miss Tessmacher, saves Superman after he promises to stop the New Jersey missile, which is headed for Hackensack, New Jersey, where her mother lives.
The rest of the film's ending, including Superman sending time backward, follows from this set up.
The problem with omnipotent superheroes is that with a little thought it's easy to mess up movie plots. If Supes is fast enough to send time backward, he's fast enough to do... a bunch of stuff.
So, here's someone's reworking of the end of the first Superman movie:
4 Good Years
8 months ago