If you don't have plans to see this movie, you can check the spoilers here and then come back.
This movie is a bit all over the place, and when it's good it's very good, but when it goes off track, it's not so much bad as incongruous and weird. The central conceit of a writer falling in love with and unwittingly giving life to his own creation is a neat one as is the idea of exploring how he tackles the challenges and temptations of building and maintaining a relationship under those unique circumstances. Problems arise when the story feels like it gets bored of its initial premise and starts wandering into romantic comedy and even psychological thriller territory without sensible transitions; what I mean to say is while I enjoy the excursion to Calvin (the writer) and Ruby (the creation) visiting his kooky mom and her hippie new lover (Annette Bening and Antonio Banderas, who both absolutely kill it), it feels like a different--and potentially good--movie wedged into the existing one awkwardly and then not fully explored. Zoe Kazan--who is a revelation starring as Ruby, incredibly magnetic and able to nail a wide range of emotions--wrote a good script as far as the dialogue and the basic gist, but I think she overreached at times with her plot and wanted to add on too many additional story points. I also feel like Paul Dano, who plays Calvin, while a fine actor, comes off way more genuine during the parts where he's manic, which is fine, but also makes it tough to buy his performance during the all-important tender moments. Chris Messina holds the whole thing together as Calvin's older brother, managing to be both a condescending jerk and also a believably caring and intelligent brother--no easy feat--while Elliot Gould makes the most of a small role as Calvin's therapist; Steve Coogan doesn't do much for me as the sleazy would-be mentor type you'd expect Steve Koogan to play. I didn't really notice the directing, which is to say Jonathan Dayton and Valerie Faris did a good if not memorable job, but it's really Kazan's movie, so perhaps it was best for them to stay out of the way. I enjoyed this well enough, but I think I'd more heartily recommend it were it a half hour shorter and a measure more focused. I do expect great things to come from Zoe Kazan.