Fridge / Adaptation.

• The movie's drastic tonal shift happens after Charlie asks Donald for advice on his script, leading me to believe that the last act of the film is to be interpreted as having been "written" by Charlie's overzealous brother. Remember how Donald's script seems to be the most cliche-ridden, mainstream Hollywood thing imaginable? That's exactly what the film becomes after Charlie asks for Donald's help in writing his script. The fact that Donald doesn't exist in real life is irrelevant.

• Fridge Brilliance:
  • As noted below, the movie becomes a thriller when Donald becomes co-screenwriter
  • In the beginning, when talking to the producer, Charlie mentions everything he doesn't want in the film: drug trafficking, sex scenes, shootouts, car chases, etc. Guess what happens in the last 30 minutes
    • In a similar tact, when Charlie sees Robert McKee's talk, McKee rants about the laziness of voiceovers (which are used extensively throughout the film) and Deus ex Machina
    McKee: I'll tell you a secret. A last act makes a film. You can have flaws, problems, but wow them in the end and you've got a hit.
  • Charlie describes in his tape recorder several scenes we actually see (like the opening monologue, the birth of the universe scene, and the introduction of La Roche).
  • Donald's script The 3 is about a man with multiple personality disorder where the man is a killer, his own hostage, and a cop chasing himself. Charlie is holding himself hostage with his insecurities and Donald is an aspect of his own personality seeking to "free" him from these neuroses.
  • Donald thinks that the same actor should play all three roles, and when Charlie asks how, Donald mentions "trick photography". Charlie finds this incredibly stupid. Both Charlie and Donald are played Nicolas Cage.
  • Another example, particularly visible if you watch this movie in a double feature with Being John Malkovich. Donald notes that for The 3, he's decided upon a running theme of broken mirrors to highlight the protagonist's fractured psyche. Being John Malkovich notably features more than a few broken mirrors as John Cusack's character became increasingly disconnected with reality.
  • The film's story itself seems to tell a somewhat realistic version of Charlie's real life process of writing the screenplay, albeit with a fictional twin brother written in. Donald represents Charlie's sell-out tendencies and anxieties over pleasing Hollywood filmmakers, and he has to eventually give in to those aspects of himself in order to write a good movie... but then adds the twist of it being his brother suddenly altering the reality of the film to preserve his own idiosyncratic style while not insulting the writer of the book, as long as she understands the metafiction behind the third act genre shift.