I just saw it this afternoon. Here's my take:
Overall, I liked the movie. It is not without faults, but most of them are .... pre-production(?) problems. By that I mean, all the critics' review which blast MNS are pretty accurate. Most of the problem lies in the structure of the story, not the story itself.
MNS writes himself too big of a character in the movie, but that isn't really that bad, imho. It is possibly quite egocentric when you learn the fate of this character, however.
He even preemptively rips on the critics (or retaliation for previous poor reviews?) by writing in a movie critic who really isn't necessary. The critic is deceitful, cowardly, and [lost the word]. Is he trying to tell us something??
Giamatti is very good in his role, but I wasn't convinced that Howard has the acting chops necessary to make it without her father's name.
The plot is pretty good, but falls victim to its own weight. It meanders and never really seems to want to get going. Or at least it doesn't show it. It tries to obfuscate the characters and their roles in the story, but it seems more a plot device than anything real. You might not always see how things are being misdirected, but you can sense that you are purposely being misdirected.
Some of the dialogue is forced. This movie REALLY needed someone to tighten up the script and screenplay - someone to tell MNS, "Umm, no, that is stupid. How 'bout if you try it this way." Unfortunately he didn't allow that, because it could have worked SO much better.
All said and done, it is a touching story, even though it sometimes seems a bit manipulative and melodramatic.
****SPOILER*******
Overall the special effects are pretty good. If you've seen the previews, you've seen the "wolf" creature. I thought that was done pretty well. There are other creatures that aren't shown until the very end; I think those would have been better left out or never shown in detail. They appeared fake to me and could have been shown out of focus or in the shadows to better effect, imo.
The most merciful thing in the world, I think, is the inability of the human mind to correlate all its contents. ... The piecing together of dissociated knowledge will open up such terrifying vistas of reality, and of our frightful position therein, that we shall either go mad from the revelation or flee from the light into the peace and safety of a new dark age.
~ Howard Phillips Lovecraft