Read the novel. Don't wast your time on this film
I have been a huge Nick Hornby fan since I read High Fidelity when I was 18. He is a brilliant author and A Long Way Down is widely considered his best novel. I love the novel and have read it multiple times. I recommend it to almost everyone who asks me what some of my favorite books are.
This film is a terrible bastardization of the book. Everyone is miscast (Toni Colette gives a good pretty performance but she is not Maureen from the novel). Very little of the novel is actually in the film and we're left with a shell of the novel and a cliched film.
Originally Johnny Depp bought the film rights and hired one of the screenwriters who wrote High Fidelity (the best adaptation of a Nick Hornby novel). I really wish we had gotten that film instead of this one.