The law of diminishing returns: It's the law--obey it! Someone should have posted that sign on the set of this, the third sequel to the film based on the DC Comics superhero. The "IV" in the title refers to medical supplies needed to resuscitate this anemic retread. This one reportedly was a pet project of actor Christopher Reeve, whose career seemed to flounder whenever he tried a role minus the blue underwear and red cape. Before agreeing to don the suit one more time, he insisted on a script that preached nuclear disarmament. So, in this film, Superman rounds up all the missiles and warheads and flings them into outer space. Which still leaves him to contend with Lex Luthor, who has a secret weapon: Nuclear Man. Yawn. Having pushed the envelope of special effects in the first film, it seemed as if the filmmakers simply stopped trying with this one. --Marshall Fine