This is a dark drama about a couple, but it never feels depressing because it's so beautifully acted that, if one doesn't appreciate the film's relatable honesty (missing in so many romance stories), one falls in love with the characters. This is due to Michelle Williams and especially Ryan Gosling doing their best work to date. They're able to convey the wonderful texture of the script, which makes these characters so believable and often quite funny and sweet, which provides a breather from very serious stuff.
The plot is deceptively simple. It moves back and forth in time between the present-day, when our characters are having trouble in their marriage, and when they first meet. Some critics have rightly noted that the story perhaps morally favors one character over another. Yet, relationships can be uneven that way, and the film isn't necessarily trying to make a statement about all women and men anyway -- just these two characters. Furthermore, one can always sympathize with the more unlikable character; I was shocked to even forget that character's present-day faults when observing that it do something so simple in the past as smile. My one criticism of the film is that it perhaps allows the more likable character to remain that way by leaving its past more shrouded in mystery. Nevertheless, that character's shabby appearance in the present lets the audience know that perhaps there is more dissatisfaction going on than that character is vocalizing.
I love this film. It is sometimes joyful, but mostly heavy, so be prepared. However, I find it much more uplifting than romantic dramas that are forced in their optimism by making their characters unrealistic or, like so many romantic comedies, focussed on populating male-driven stories with gorgeous yet vapid women with whom the protagonists "score." This is a great and beautiful film because it is emotionally resonant with my own life and the world in which we actually live.