I like that this is "dick lit" and a response to things like Bridget Jones' Diary. Thank you Goodreads friends for providing that encapsulating term. However, this would be better with even a marginally likeable protagonist. I appreciate that for the film, they made him a distinctly less despicable human being. Not good, mind you, just less broken. 
 I would like it more if it had actually gone for the gender subversion of the princess being rescued by the white knight, but its cleverness is spent elsewhere. 
 This book also suffers from things that will age poorly with time, and are already suffering. The local slangy "of the time and place" parts and the fact that it's centered around a record store. Obscure and esoteric bands tend to get more obscure and esoteric.