This was one of my favorite movies the first time I saw it. After seeing 'What Lies Beneath', I would have to say that, as much as I love Back to the Future, I like Zemeckis' darker films best. I absolutely loved Bruce Willis in this movie.
Also, the use of film manipulation and special effects is excellent for its' time in this movie, and is still easily appreciated even now. What I love best about Zemeckis, has to be his use of the passing of time in his movies. Huge time lines are crammed into a few chapters! It's amazing. Characters age. It's so great. And, as always, there is just the right amount of imagination in this film. One of his best!