normally i am not one for seeing movie adaptations of books that i thoroughly enjoy. but when i saw the trailer for gone girl, i knew i’d go see this one.
ahem: *spoilers!*
surprisingly, the movie sticks relatively close to the book’s plot (relatively because i’ve seen books veer so off course, it’s a new plot). there are a few embellishments, like the scene where amy kills desi. in the book, she drugs his wine and then stabs him. in the movie, she swipes his neck with a boxcutter midcoitus. and it is VERY bloody (and we see neil patrick harris’ junk covered in blood).
the end is also toyed with a little, but the things that need to get done get done. 
the movie is classic david fincher: dark, shadowy, moody. when one of my movie mates afterward said it was like no one acted in the movie, i thought, huh. i thought they acted out the characters exactly. but then, the characters in the book are doing nothing but acting the whole time, aren’t they? we never really know who amy is, and nick is trying to cover up so much stuff that he has to have the ultimate poker face.
the movie, while entertaining, is not as engrossing as the book (as is always the case). i recently reread the book and once again could barely put it down. it helps to know the psychopathic nuances going into the movie, because afterward, the people i saw the movie with weren’t entirely impressed with it. meanwhile, i was thinking, hey, that was a pretty darn good adaptation. 
what did i not like? NPH would not have been the person i’d’ve chosen for desi. at the end of the book, nick realizes that he doesn’t hate all women; he hates amy. in the movie, i got the impression otherwise. we did not get the sense of complete helplessness from nick when amy gets pregnant – it’s more like he’s just manning up to his responsibility rather than in the book where he was overwhelmed by the thought of his kid. also, there is a moment at the end where nick slams amy’s head against the wall, which is NOT something i would have done. i know nick hates amy, but come on. we want to keep that better image of nick. 
was it as good as the book? no. was it a well-done movie? i think so, but then i’m biased because i was so enamored by the book.