This is the last and weakest of the Scott Pilgrim novels. The entire last half is the climatic fight. It also has the main characters Scott and Ramona maturing in their attitude to relationships. However, it seems to me that they have moved from one dysfunctional way of thinking about relationships to another. Moralizing does not really suit the story or Bryan Lee O'Malley's strengths.
Having said that the Scott Pilgrim books are a major work in graphic literature and while they weaken as they go along (one gets the feeling that the author is growing tired of them) they are still essential reading, innovative and very clever. There combination of pop-culture nerd references combined with the slacker lifestyle of lost people in their early twenties is well done and spot on. The characters are sharply drawn and well realized. The series as a whole is a landmark achievement, even though this is the weakest of the six.