^ I thought I remember reading that they were considering Brainiac as a villain (hence the focus on the super computers and such), but opted out.
Then again, a lot of Superman's villains would have been hard to pull off, effects-wise, in the early 80s.
How? I think a lot of 80s films had decent effects, given the computing power at the time. Maybe Bizarro, with Christopher Reeve playing a triple role, could have worked. The prosthetics of the time could have pulled it off. Reeve had the acting skills to do it, that I don't doubt.