In principle there could be a great movie here. In practice, like others have said, the idea seems to have been to pack multiple movies into one, and that rarely works.
Let's move past the banal question of whether it was "faithful to the book" and consider it on its own merits. There's the kernel of a great idea here, a film that luxuriates in movie trivia and in explaining technical details, while constantly having fun with the idea of ignoring the movie filming timeline of our reality (cf the catchphrase "f$%# continuity", writ large).
The problem is that Franco makes three rookie mistakes.
- he doesn't stick to *that* movie; instead he insists on throwing in other stories, most jarringly the Soledad love story. Look, we get it, Megan Fox is pretty. But that doesn't mean she has to be used (and used up) in the most boring way possible. Compare with the much more interesting use of Dottie, not as love interest but as teacher/explainer of Editing.
- movies (and books) about obsession, about "here's how much I love something and why" can be done well. But again, you have to avoid the rookie mistake: the book has to be about obsession *generically*, not about your particular obsession. Once you list details, every person on earth (and that's most of them) who doesn't agree with your exact ranking of first through tenth greatest whatever's loses interest.
That's why Juliet, Naked is so much better a movie than High Fidelity (oh shut up, you know it's true!) because they both deal with obsession, but one doesn't make the mistake of going into specifics.
- third rookie mistake: "explaining" via mental illness, dreams, and visions, the crutches of the lazy and incompetent screenwriter.
You don't need to explain in a movie! The audience will happily accept magic realism -- the Simpsons have been doing it for 30+ years. Purple Rose of Cairo? True Lies? Neither of them felt a need to justify their magic realism as the product of dreams or mental illness.
Or, of course, Inglorious Basterds and Once Upon a Time in Hollywood. Again, just tell the story, don't "explain" why it doesn't match consensus reality!
Franco keeps trying with this stuff (compare _The Disaster Artist_) and I appreciate his trying. I just hope he learns from each misfire and next time executes in a more focussed fashion.
There are not enough well-done obsessive movies -- most of them are pathetic shambles, either cautionary tales about "here's how you will suffer", or watered down by including uninteresting stereotypical side plots -- and I think Franco has it in him to do the job right, once he has the courage to do it his way, not the Hollywood way.