The first time I saw it, I was suspicious about the way they featured Fallon in scenes, but assumed it was because he wasn't really an actor, it was simply a cameo by Empire movie reviewer Kim Newman:
I saw an interview with him where he talks about not wanting it to be a cop out, how he introduces things early so as not to cheat the audience. I think 'SciFi' evokes a certain image that isn't quite right for the film, but I think it is technically fictional science. I'll see if I can find the link later.
Also, to make it non-sci fi would be changing it too dramatically from the book (it already alters many aspects from the book, but I don't think that would be a change they make).
I have read many of the theories and none of them satisfy any of the questions they raise about things I can't really mention without spoiling the film.
When did you decide to go with three timelines?
CHRIS: The one thing we talked about early on was that it always felt the story needed a nonlinear structure because of the supernatural element. That came vary late in the book, and in a movie it would change the terms of the storytelling. So the whole science-fiction aspect needed to be upfront; we needed to clue people in, show them [the Tesla] machine and what's going on right from the get go.
JONAH: So that they're watching the same movie that we're making. I was gratified to see in the trailer that they emphasized that.
CHRIS: Yeah. It's very important.
