Bryan Singer was surprised by his own reaction to the movie when he showed an early cut to a test audience, and he was galvanised into trimming it down to 100 minutes.
And he is grateful for a scathing online review of the initial version - because it provided him with the perfect opening to the movie.
Bryan Singer tells Total Film magazine, "The first cut we showed to a bunch of people was so languid and terrible, I almost fell asleep during it, my own movie. I didn't mean for it to be screened that early, and then someone posted a review on the internet..."
"I never told anyone this, but this horrible, mean, awful, terrible review of the slow, miserable first cut of "X-Men" inspired one thing. It was something the reviewer said, like, 'We don't even know what these mutants are!' And that gave me an idea for a preamble, Xavier's preamble... I thought, this'll become our thing, like the gun barrel at the start of James Bond, and we'll have it in front of every movie. So as much as I hate those evil internet reviews, it actually helped me come up with that!"