Let me tell you a little of my experience watching this movie.

Empire was the first SW movie I actually saw in cinema. I vividly remember all the hype surrounding it. There was a promotion tour before where Darth Vader and some Stormtroopers visited stores and even signed autographs. Sounds funny today but I was about 11 and I loved that stuff. Of course they weren't the real actors but I wanted to be a Stormtrooper anyway. I think I still have the Darth Vader signature somewhere. (Meanwhile I have the ones of Prowse and Jones, too)
When the big reveal in the movie came the cinema was stunned. Even thought the movie premiered about half a year before in the States it was still possible to keep things under wraps with no internet. There were rumors spread by people who watched it but nothing solid. And it was hard to believe anyway. So there was real astonishment and fright upon the revelation. Don't you miss that ? Today there is hardly anything in a movie that is surprising and it's tough to avoid spoilers which can come from the most unexpected angles.
As an 11 year old I wasn't analyzing the movie, I simply loved and enjoyed every second of it. Even today I have no favorite among the original trillogy. I see them as a whole and they are close to my heart. Back then Empire solidified my love for Star Wars and I was very eager to know how it would continue.
How would they rescue Han ? What will Luke do now that he knew his father is the Evil personified ? There were many things to talk about and our imagination ran wild.