It took far too long for the first film to be made, and even then it wasn’t smooth sailing. The script floated around Hollywood for years, a lot of executives wanted to meddle even after Universal Studios picked it up.
Stoltz was replaced with Fox, and even after Fox signed on, he was running on fumes filming both this and the show “Family Ties”, leading to a few breakdowns and nightmares for Fox. It made his acting in Back to the Future a little more lifelike, but it was still a rough time.
A Hostile Set
One of the reasons Fox was brought in so quickly was because Stoltz was something of a prima donna. Others thought he was too serious for the role, and so when Fox finished his latest project, Stoltz was out and Fox was in.
Neither Tom Wilson nor Crispon Glover got along well with Stoltz, according to them. In addition, Glover proved to be quite more demanding than his character — argumentative, and often battling with director Robert Zemeckis. But, thanks to Stoltz being fired, many of the actors were frightened of doing too much, thinking their jobs might be in danger.
Improvisation Brings the Laughs
In every movie, there will be scenes of ad-libbing or throwing in details that the filmmakers hadn't envisioned, and the "BttF" movies are no exception. Most of George McFly's mannerisms are just Crispin Glover acting naturally or putting his spin on the character, such as his laugh at the episode of "Honeymooners".
He had to try and act “naturally” for the scenes of his improved 1985 self. Huey Lewis actually improvised the line of “I'm afraid you're just too darn loud.”
No Sequel Intended
Every version of the movie these days will have the bright, colorful “To Be Continued” card at the end of the film as Doc Brown, Marty, and Jennifer take off.
This wasn't present in the first cut of the film, since the filmmakers had no intention of continuing the series, and the “cliffhanger” ending was made as a joke. Yet the film went on to break records and garner immense praise, and so a sequel appeared anyway. The “To Be Continued” card was hurriedly added to the home video release in order to advertise "Back to the Future Part II".
A Long-Running Series
"Back to the Future II" is set in the distant future of 2015. Things didn't exactly match up to what the filmmakers had envisioned, but they probably don't care. There's no hoverboard, and there's no way the "Jaws" franchise got nineteen movies.
The huge hologram that sprang out of the movie theater was inspired by the incredible number of sequels "Jaws" spawned in such a short time – four had already come out by the time of "Back to the Future Part II". After that, however, the series pretty much tanked, and not even Steven Spielberg's son (“Max” in the movie) is interested in resurrecting it.