If you don't have plans to see this movie, you can check the spoilers here and then come back.
The premise here--down-on-her-luck single mom and her bad seed sister make cash by cleaning up crime scenes--is a neat gimmick and decent hook, but really more just a clever set-for a group of talented actors to do what they do best. However, as much as this film was more of an actor's showcase to me, I don't want to undersell the script, which did a nice job of balancing dark comedy with some real heavy stuff centered on loss and family. It's no surprise to me any time Amy Adams turns in an amazing performance, but she was really on top of her game here, convincingly playing Rose, whose life has taken every turn possible and infusing her with real likeability, making you want to root for her; she's also truly masterful at infusing scenes with awkward energy, which makes for some excellent comedy. Complenting Adams, Emily Blunt slips into the role of slacker Norah nicely, really inhabiting the character and making her feel like a real person, complete with quirks and flaws you want to learn more about. The chemistry between Adams and Blunt is wonderful, as you really do believe they're sisters and they work so naturally, making their scenes a real delight. The side scenes mostly involve the girls' dad, played as a wayward but lovable aging deal-seeker by the great Alan Arkin, giving Rose's son, Oscar, the wonderfully precocious Jason Pevack, lessons in life. Mary Lynn Rajskub and Steve Zahn--playing way against type--round out the ensemble, but the movie's biggest revelation for me was Clifton Collins Jr. as Winston, the soft-spoken one-armed cleaning supplies salesman who tutors the girls and totally charms you in the process without even really trying. If I have any real complaints about this film it's that I felt like a lot of the relationships and issues didn't get fully explored or resolved, and given that it ran only 90 minutes, I would have gladly accepted another half hour at least to give those outstanding bits room to breathe (also, Eric Christian Olsen was wasted in basically a cameo, but what can you do). Ultimately, this movie has a lot of heart and really welcomes you in to it's world for an enriching if slightly unsettling (did I mention the blood and maggots?) experience.