Oh, no problem – this thread was getting cumbersome with all the huge spoiler boxes anyhow.
Here’s my take on Ofelia’s choice of the left door during the 2nd test:
Every indication we’re given points to the idea that the center door is the correct choice – the faun’s guide-fairies insist on it, and apparently the book shows her using the center door (although I don’t remember seeing this). She even hesitantly places the key into the lock of the center door, and just as she’s about to open the lock, she recoils violently and goes for the left door.
I’m guessing she is acting on some kind of powerful intuition telling her to pick the left door (and apparently she’s right, although we’ll never know what was behind the center door).
I may be venturing into left-field territory now, but I have a theory as to what drove her impulsive, last-second decision. If you think back to the beginning of the film, when she first meets the Capitan, she offers him her left hand and he refuses, curtly telling her that she should have offered the right hand. This illustrates the strict, petty nature of the Capitan, and I think it also suggests a bit of rebellion on the part of Ofelia (either conscious or unconscious). Perhaps she simply forgets her etiquette, or perhaps she offers the “wrong” hand on purpose to test him.
In any case, I’m thinking Ofelia’s impulse to pick the left door might stem from her belief that the Capitan would never choose it, and her primal desire to defy his will. So her very first act of disobedience in the fantasy world is subtley linked to her first act of defiance toward the Capitan in the real world. (Admitedly the parallel would be clearer had there only been two doors, which is why I think I may be reaching a bit.)
As for eating the food:
I’m not sure the food is enchanted, although I suppose anything’s possible in a fairy tale. I think she has plenty of motivation to eat the food without any extra magic to tempt her – she was sent to bed without food so she’s likely very hungry, and more importantly, her confidence has been bolstered by the fact that she already disobeyed the “rules” once by opening the left door, so maybe she suspects the rule about not eating the food is bunk too. It’s pretty normal for kids to test the limits like this, although obviously it’s a dumb move (or maybe not).
Perhaps Del Torro’s theme is more nuanced than “obedience=bad, choice=good”. Maybe by showing Ofelia making some bad choices, he’s trying to emphasize that sometimes obedience is the correct path, and other times it’s not – what’s more important is the ability to make this distinction.