4) Back To The Future
Back to the Future almost wasn’t the classic we know today. It took an extra $3 million and an additional five weeks of shooting to undo what writer-director Robert Zemeckis came to see was a movie-sinking mistake: casting Eric Stoltz as Marty McFly. More than a month into the shoot, Zemeckis sent Stoltz on his way, replaced him with Michael J. Fox in the lead, and started from scratch.
It wasn’t just Back to the Future‘s lead actor that changed with reshoots, either. In fact, Michael J. Fox changed the entire tone of the film. Whereas Stoltz played Marty McFly “terrifically dramatic” (Zemeckis’ words), Fox brought a completely different energy. Basically, he turned the movie into a comedy, rather than the bittersweet drama Stoltz was making.
3) The Invasion
There have, over the years, been several great adaptations of Jack Finney’s sci-fi novel The Body Snatchers; 2007’s The Invasion isn’t one of them. By most critics’ reckoning, the movie’s all over the place, and undoubtedly the main reason it’s so muddled is that the film – originally directed by Oliver Hirschbiegel – was worked over by four directors in total.
Hirschbiegel was going for an ideas-driven sci-fi high in tension, which used minimal effects and zero greenscreen work. This did nothing for studio Warner Bros, however, who hired the Wachowskis and James McTeigue to action up the film, re-write a portion of it and – perhaps most significantly – add a new twist ending. And voila: the final movie, low on plot and high on explosive action, reportedly looks nothing like Hirschbiegel’s vision.