I watched the movie at least 10 times when it was in the theatres. Later on I got it on VHS and I now have it on DVD, plus seeing it sometimes on TV and sometimes in second run threatres. And I was a grown up person when it came out. So my memory of the movie is quite clear and not glossed over with nostalgia--even though I'm nostalgic for the movie and the times when I saw it back then.
I remember quite well my reaction to the movie and the reaction of family and friends. There are parts that are deliberately cheesy and they're there for effect. I'm a Canadian--but Canadians are very good observers of the Amercian experience (it's one of our national pastimes).
Around the time of the Bicentennial, there was a growing desire in the States to feel good about yourselves. The USA had gone through the Vietnam War and Watergate--plus assassinations and other upheavals--that caused a national identity crisis. A lot of movies and TV shows depicted the country in a negative light, but there was a growing effort to bring back a sense of national pride.
The beginning bit of STM is cheesy but becomes awesome. In fact, the first thing you saw in the theatre was the red S projected on the theatrre screen curtains. Those curtains open and then you see black and white curtains that open and a black and white movie which is quaint and reminds the audience of simpler times and the cheesy old comics and movies about Superman, but as the camera goes past the spinning "Daily Planet" globe, we're transported into outer space and into a completely different reality--which is awesome.
That's a thematic approach throughout the move. We're deliberately shown things that are reminders of simpler times in America and then those elements are turned and shown in a new light as truly awesome. It was a clever and insightful way to get Americans to look at their culture with a new sense of what it meant. Superman himself comes across as superficial, but the more we see his psychological struggle and understand his philosophical position, we come to love him in a profound way--just as Americans returned to loving their country in a meaningful way.
The three movies that followed SUPERMAN THE MOVIE went down and down in quality. It's hard to watch either SUPERMAN III or THE QUEST FOR PEACE all the way through--those movies really make me cringe. But SUPERMAN THE MOVIE had a clear vision and every scene in the movie is there for a reason.